configcat-common - npm Package Compare versions

Comparing version 6.0.1 to 7.0.0

lib/AutoPollConfigService.d.ts

 import { AutoPollOptions } from "./ConfigCatClientOptions";
-import { IConfigService, ConfigServiceBase } from "./ConfigServiceBase";
-import { IConfigFetcher } from "./index";
+import type { IConfigFetcher } from "./ConfigFetcher";
+import { ConfigServiceBase, IConfigService, RefreshResult } from "./ConfigServiceBase";
 import { ProjectConfig } from "./ProjectConfig";
-export declare class AutoPollConfigService extends ConfigServiceBase implements IConfigService {
-    private maxInitWaitTimeStamp;
-    private configChanged;
-    private timerId;
-    private autoPollConfig;
-    private disposed;
-    constructor(configFetcher: IConfigFetcher, autoPollConfig: AutoPollOptions);
+export declare class AutoPollConfigService extends ConfigServiceBase<AutoPollOptions> implements IConfigService {
+    private initialized;
+    private initialization;
+    private signalInitialization;
+    private timerId?;
+    constructor(configFetcher: IConfigFetcher, options: AutoPollOptions);
+    private waitForInitializationAsync;
     getConfig(): Promise<ProjectConfig | null>;
-    refreshConfigAsync(): Promise<ProjectConfig | null>;
+    refreshConfigAsync(): Promise<[RefreshResult, ProjectConfig | null]>;
     dispose(): void;
-    private refreshLogic;
+    protected onConfigUpdated(newConfig: ProjectConfig): void;
+    protected onConfigChanged(newConfig: ProjectConfig): void;
+    protected setOnlineCore(): void;
+    protected setOfflineCore(): void;
     private startRefreshWorker;
+    private stopRefreshWorker;
     private refreshWorkerLogic;
-    private tryReadFromCache;
-    private sleep;
 }
 //# sourceMappingURL=AutoPollConfigService.d.ts.map

lib/AutoPollConfigService.js

 "use strict";
-var __extends = (this && this.__extends) || (function () {
-    var extendStatics = function (d, b) {
-        extendStatics = Object.setPrototypeOf ||
-            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
-            function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
-        return extendStatics(d, b);
-    };
-    return function (d, b) {
-        if (typeof b !== "function" && b !== null)
-            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
-        extendStatics(d, b);
-        function __() { this.constructor = d; }
-        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
-    };
-})();
-var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
-    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
-    return new (P || (P = Promise))(function (resolve, reject) {
-        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
-        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
-        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
-        step((generator = generator.apply(thisArg, _arguments || [])).next());
-    });
-};
-var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
-    function verb(n) { return function (v) { return step([n, v]); }; }
-    function step(op) {
-        if (f) throw new TypeError("Generator is already executing.");
-        while (_) try {
-            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
-            if (y = 0, t) op = [op[0] & 2, t.value];
-            switch (op[0]) {
-                case 0: case 1: t = op; break;
-                case 4: _.label++; return { value: op[1], done: false };
-                case 5: _.label++; y = op[1]; op = [0]; continue;
-                case 7: op = _.ops.pop(); _.trys.pop(); continue;
-                default:
-                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
-                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
-                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
-                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
-                    if (t[2]) _.ops.pop();
-                    _.trys.pop(); continue;
-            }
-            op = body.call(thisArg, _);
-        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
-        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
-    }
-};
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.AutoPollConfigService = void 0;
+var tslib_1 = require("tslib");
 var ConfigServiceBase_1 = require("./ConfigServiceBase");
 var ProjectConfig_1 = require("./ProjectConfig");
+var Utils_1 = require("./Utils");
 var AutoPollConfigService = /** @class */ (function (_super) {
-    __extends(AutoPollConfigService, _super);
-    function AutoPollConfigService(configFetcher, autoPollConfig) {
-        var _this = _super.call(this, configFetcher, autoPollConfig) || this;
-        _this.disposed = false;
-        _this.configChanged = autoPollConfig.configChanged;
-        _this.autoPollConfig = autoPollConfig;
-        _this.startRefreshWorker(autoPollConfig.pollIntervalSeconds * 1000);
-        _this.maxInitWaitTimeStamp = new Date().getTime() + (autoPollConfig.maxInitWaitTimeSeconds * 1000);
+    tslib_1.__extends(AutoPollConfigService, _super);
+    function AutoPollConfigService(configFetcher, options) {
+        var _this = _super.call(this, configFetcher, options) || this;
+        _this.signalInitialization = (void 0); // the initial value is only for keeping the TS compiler happy
+        if (options.maxInitWaitTimeSeconds > 0) {
+            _this.initialized = false;
+            // This promise will be resolved when
+            // 1. the cache contains a valid config at startup (see startRefreshWorker) or
+            // 2. config.json is downloaded the first time (see onConfigUpdated) or
+            // 3. maxInitWaitTimeSeconds has passed (see the setTimeout call below).
+            _this.initialization = new Promise(function (resolve) { return _this.signalInitialization = function () {
+                _this.initialized = true;
+                resolve();
+            }; });
+            _this.initialization.then(function () { return !_this.disposed && options.hooks.emit("clientReady"); });
+            setTimeout(function () { return _this.signalInitialization(); }, options.maxInitWaitTimeSeconds * 1000);
+        }
+        else {
+            _this.initialized = true;
+            _this.initialization = Promise.resolve();
+            options.hooks.emit("clientReady");
+        }
+        if (!options.offline) {
+            _this.startRefreshWorker(options.pollIntervalSeconds * 1000);
+        }
         return _this;
     }
+    AutoPollConfigService.prototype.waitForInitializationAsync = function () {
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var cancelDelay, result;
+            var _this = this;
+            return tslib_1.__generator(this, function (_a) {
+                switch (_a.label) {
+                    case 0: return [4 /*yield*/, Promise.race([
+                            (function () { return tslib_1.__awaiter(_this, void 0, void 0, function () { return tslib_1.__generator(this, function (_a) {
+                                switch (_a.label) {
+                                    case 0: return [4 /*yield*/, this.initialization];
+                                    case 1:
+                                        _a.sent();
+                                        return [2 /*return*/, true];
+                                }
+                            }); }); })(),
+                            (0, Utils_1.delay)(this.options.maxInitWaitTimeSeconds * 1000, function (cancel) { return cancelDelay = cancel; })
+                        ])];
+                    case 1:
+                        result = _a.sent();
+                        cancelDelay();
+                        return [2 /*return*/, !!result];
+                }
+            });
+        });
+    };
     AutoPollConfigService.prototype.getConfig = function () {
-        return __awaiter(this, void 0, void 0, function () {
-            var p;
-            return __generator(this, function (_a) {
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            function logSuccess(logger) {
+                logger.debug("AutoPollConfigService.getConfig() - returning value from cache.");
+            }
+            var cacheConfig;
+            return tslib_1.__generator(this, function (_a) {
                 switch (_a.label) {
                     case 0:
-                        this.autoPollConfig.logger.debug("AutoPollConfigService.getConfig() called.");
-                        return [4 /*yield*/, this.tryReadFromCache(0)];
+                        this.options.logger.debug("AutoPollConfigService.getConfig() called.");
+                        cacheConfig = null;
+                        if (!(!this.isOffline && !this.initialized)) return [3 /*break*/, 3];
+                        return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
                     case 1:
-                        p = _a.sent();
-                        if (!p) {
-                            this.autoPollConfig.logger.debug("AutoPollConfigService.getConfig() - cache is empty, refreshing the cache.");
-                            return [2 /*return*/, this.refreshLogic(true)];
+                        cacheConfig = _a.sent();
+                        if (!ProjectConfig_1.ProjectConfig.isExpired(cacheConfig, this.options.pollIntervalSeconds * 1000)) {
+                            logSuccess(this.options.logger);
+                            return [2 /*return*/, cacheConfig];
                         }
+                        this.options.logger.debug("AutoPollConfigService.getConfig() - cache is empty or expired, waiting for initialization.");
+                        return [4 /*yield*/, this.waitForInitializationAsync()];
+                    case 2:
+                        _a.sent();
+                        _a.label = 3;
+                    case 3: return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
+                    case 4:
+                        cacheConfig = _a.sent();
+                        if (!ProjectConfig_1.ProjectConfig.isExpired(cacheConfig, this.options.pollIntervalSeconds * 1000)) {
+                            logSuccess(this.options.logger);
+                        }
                         else {
-                            this.autoPollConfig.logger.debug("AutoPollConfigService.getConfig() - returning value from cache.");
-                            return [2 /*return*/, new Promise(function (resolve) { return resolve(p); })];
+                            this.options.logger.debug("AutoPollConfigService.getConfig() - cache is empty or expired.");
                         }
-                        return [2 /*return*/];
+                        return [2 /*return*/, cacheConfig];
                 }
@@ -92,92 +100,83 @@ });
     AutoPollConfigService.prototype.refreshConfigAsync = function () {
-        this.autoPollConfig.logger.debug("AutoPollConfigService.refreshConfigAsync() called.");
-        return this.refreshLogic(true);
+        this.options.logger.debug("AutoPollConfigService.refreshConfigAsync() called.");
+        return _super.prototype.refreshConfigAsync.call(this);
     };
     AutoPollConfigService.prototype.dispose = function () {
-        this.autoPollConfig.logger.debug("AutoPollConfigService.dispose() called.");
-        this.disposed = true;
+        this.options.logger.debug("AutoPollConfigService.dispose() called.");
+        _super.prototype.dispose.call(this);
         if (this.timerId) {
-            this.autoPollConfig.logger.debug("AutoPollConfigService.dispose() - clearing setTimeout.");
-            clearTimeout(this.timerId);
+            this.stopRefreshWorker();
         }
     };
-    AutoPollConfigService.prototype.refreshLogic = function (forceUpdateCache) {
-        var _this = this;
-        this.autoPollConfig.logger.debug("AutoPollConfigService.refreshLogic() - called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var cachedConfig, newConfig, weDontHaveCachedYetButHaveNew, weHaveBothButTheyDiffers;
-            return __generator(this, function (_a) {
+    AutoPollConfigService.prototype.onConfigUpdated = function (newConfig) {
+        _super.prototype.onConfigUpdated.call(this, newConfig);
+        this.signalInitialization();
+    };
+    AutoPollConfigService.prototype.onConfigChanged = function (newConfig) {
+        _super.prototype.onConfigChanged.call(this, newConfig);
+        this.options.configChanged();
+    };
+    AutoPollConfigService.prototype.setOnlineCore = function () {
+        this.startRefreshWorker(this.options.pollIntervalSeconds * 1000);
+    };
+    AutoPollConfigService.prototype.setOfflineCore = function () {
+        this.stopRefreshWorker();
+    };
+    AutoPollConfigService.prototype.startRefreshWorker = function (delayMs) {
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var latestConfig;
+            var _this = this;
+            return tslib_1.__generator(this, function (_a) {
                 switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.baseConfig.cache.get(this.baseConfig.getCacheKey())];
+                    case 0:
+                        this.options.logger.debug("AutoPollConfigService.startRefreshWorker() called.");
+                        return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
                     case 1:
-                        cachedConfig = _a.sent();
-                        return [4 /*yield*/, this.refreshLogicBaseAsync(cachedConfig, forceUpdateCache)];
+                        latestConfig = _a.sent();
+                        if (!ProjectConfig_1.ProjectConfig.isExpired(latestConfig, this.options.pollIntervalSeconds * 1000)) return [3 /*break*/, 4];
+                        if (!!this.isOfflineExactly) return [3 /*break*/, 3];
+                        return [4 /*yield*/, this.refreshConfigCoreAsync(latestConfig)];
                     case 2:
-                        newConfig = _a.sent();
-                        weDontHaveCachedYetButHaveNew = !cachedConfig && newConfig;
-                        weHaveBothButTheyDiffers = cachedConfig && newConfig && !ProjectConfig_1.ProjectConfig.equals(cachedConfig, newConfig);
-                        this.autoPollConfig.logger.debug("AutoPollConfigService.refreshLogic() - weDontHaveCachedYetButHaveNew: ." + weDontHaveCachedYetButHaveNew + ". weHaveBothButTheyDiffers: " + weHaveBothButTheyDiffers + ".");
-                        if (weDontHaveCachedYetButHaveNew || weHaveBothButTheyDiffers) {
-                            this.configChanged();
-                        }
-                        resolve(newConfig);
+                        _a.sent();
+                        _a.label = 3;
+                    case 3: return [3 /*break*/, 5];
+                    case 4:
+                        this.signalInitialization();
+                        _a.label = 5;
+                    case 5:
+                        this.options.logger.debug("AutoPollConfigService.startRefreshWorker() - calling refreshWorkerLogic()'s setTimeout.");
+                        this.timerId = setTimeout(function (d) { return _this.refreshWorkerLogic(d); }, delayMs, delayMs);
                         return [2 /*return*/];
                 }
             });
-        }); });
-    };
-    AutoPollConfigService.prototype.startRefreshWorker = function (delay) {
-        var _this = this;
-        this.autoPollConfig.logger.debug("AutoPollConfigService.startRefreshWorker() called.");
-        this.refreshLogic(true).then(function (_) {
-            _this.autoPollConfig.logger.debug("AutoPollConfigService.startRefreshWorker() - calling refreshWorkerLogic()'s setTimeout.");
-            setTimeout(function () { return _this.refreshWorkerLogic(delay); }, delay);
         });
     };
-    AutoPollConfigService.prototype.refreshWorkerLogic = function (delay) {
-        var _this = this;
-        if (this.disposed) {
-            this.autoPollConfig.logger.debug("AutoPollConfigService.refreshWorkerLogic() - called on a disposed client.");
-            return;
-        }
-        this.autoPollConfig.logger.debug("AutoPollConfigService.refreshWorkerLogic() - called.");
-        this.refreshLogic(false).then(function (_) {
-            _this.autoPollConfig.logger.debug("AutoPollConfigService.refreshWorkerLogic() - calling refreshWorkerLogic()'s setTimeout.");
-            _this.timerId = setTimeout(function () {
-                _this.refreshWorkerLogic(delay);
-            }, delay);
-        });
+    AutoPollConfigService.prototype.stopRefreshWorker = function () {
+        this.options.logger.debug("AutoPollConfigService.stopRefreshWorker() - clearing setTimeout.");
+        clearTimeout(this.timerId);
     };
-    AutoPollConfigService.prototype.tryReadFromCache = function (tries) {
-        return __awaiter(this, void 0, void 0, function () {
-            var p, diff, delay;
-            return __generator(this, function (_a) {
+    AutoPollConfigService.prototype.refreshWorkerLogic = function (delayMs) {
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var latestConfig;
+            var _this = this;
+            return tslib_1.__generator(this, function (_a) {
                 switch (_a.label) {
                     case 0:
-                        this.autoPollConfig.logger.debug("AutoPollConfigService.tryReadFromCache() - called. Tries: " + tries + ".");
-                        return [4 /*yield*/, this.baseConfig.cache.get(this.baseConfig.getCacheKey())];
+                        if (this.disposed) {
+                            this.options.logger.debug("AutoPollConfigService.refreshWorkerLogic() - called on a disposed client.");
+                            return [2 /*return*/];
+                        }
+                        this.options.logger.debug("AutoPollConfigService.refreshWorkerLogic() - called.");
+                        if (!!this.isOffline) return [3 /*break*/, 3];
+                        return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
                     case 1:
-                        p = _a.sent();
-                        if (!(this.maxInitWaitTimeStamp > new Date().getTime()
-                            && (
-                            // Wait for maxInitWaitTimeStamp in case the cache is empty
-                            !p
-                                // Wait for maxInitWaitTimeStamp in case of an expired cache (if its timestamp is older than the pollIntervalSeconds)
-                                || p.Timestamp < new Date().getTime() - this.autoPollConfig.pollIntervalSeconds * 1000))) return [3 /*break*/, 3];
-                        if (!p) {
-                            this.autoPollConfig.logger.debug("AutoPollConfigService.tryReadFromCache() - waiting for maxInitWaitTimeStamp because cache is empty.");
-                        }
-                        else {
-                            this.autoPollConfig.logger.debug("AutoPollConfigService.tryReadFromCache() - waiting for maxInitWaitTimeStamp because cache is expired.");
-                        }
-                        diff = this.maxInitWaitTimeStamp - new Date().getTime();
-                        delay = 30 + (tries * tries * 20);
-                        return [4 /*yield*/, this.sleep(Math.min(diff, delay))];
+                        latestConfig = _a.sent();
+                        return [4 /*yield*/, this.refreshConfigCoreAsync(latestConfig)];
                     case 2:
                         _a.sent();
-                        tries++;
-                        return [2 /*return*/, this.tryReadFromCache(tries)];
+                        _a.label = 3;
                     case 3:
-                        this.autoPollConfig.logger.debug("AutoPollConfigService.tryReadFromCache() - returning value from cache.");
-                        return [2 /*return*/, new Promise(function (resolve) { return resolve(p); })];
+                        this.options.logger.debug("AutoPollConfigService.refreshWorkerLogic() - calling refreshWorkerLogic()'s setTimeout.");
+                        this.timerId = setTimeout(function (d) { return _this.refreshWorkerLogic(d); }, delayMs, delayMs);
+                        return [2 /*return*/];
                 }
@@ -187,7 +186,4 @@ });
     };
-    AutoPollConfigService.prototype.sleep = function (ms) {
-        return new Promise(function (resolve) { return setTimeout(resolve, ms); });
-    };
     return AutoPollConfigService;
 }(ConfigServiceBase_1.ConfigServiceBase));
 exports.AutoPollConfigService = AutoPollConfigService;

lib/Cache.d.ts

 import { ProjectConfig } from "./ProjectConfig";
-import { ICache } from "./index";
+export interface ICache {
+    set(key: string, config: ProjectConfig): Promise<void> | void;
+    get(key: string): Promise<ProjectConfig | null> | ProjectConfig | null;
+}
 export declare class InMemoryCache implements ICache {
@@ -8,4 +11,4 @@ cache: {
     set(key: string, config: ProjectConfig): void;
-    get(key: string): ProjectConfig;
+    get(key: string): ProjectConfig | null;
 }
 //# sourceMappingURL=Cache.d.ts.map

lib/Cache.js

@@ -12,3 +12,4 @@ "use strict";
     InMemoryCache.prototype.get = function (key) {
-        return this.cache[key];
+        var _a;
+        return (_a = this.cache[key]) !== null && _a !== void 0 ? _a : null;
     };
@@ -15,0 +16,0 @@ return InMemoryCache;

lib/ConfigCatClient.d.ts

@@ -1,26 +0,52 @@
-import { IConfigCatKernel } from "./index";
-import { AutoPollOptions, ManualPollOptions, LazyLoadOptions } from "./ConfigCatClientOptions";
-import { User } from "./RolloutEvaluator";
-export interface IConfigCatClient {
+import type { ICache } from "./Cache";
+import { ConfigCatClientOptions, OptionsForPollingMode, PollingMode } from "./ConfigCatClientOptions";
+import type { IConfigFetcher } from "./ConfigFetcher";
+import { RefreshResult } from "./ConfigServiceBase";
+import type { IEventEmitter } from "./EventEmitter";
+import type { HookEvents, IProvidesHooks } from "./Hooks";
+import { IEvaluationDetails, SettingTypeOf, SettingValue, User, VariationIdTypeOf, VariationIdValue } from "./RolloutEvaluator";
+export interface IConfigCatClient extends IProvidesHooks {
+    /** Returns the value of a feature flag or setting based on it's key
+     * @deprecated This method is obsolete and will be removed from the public API in a future major version. Please use the getValueAsync() method instead.
+     */
+    getValue<T extends SettingValue>(key: string, defaultValue: T, callback: (value: SettingTypeOf<T>) => void, user?: User): void;
     /** Returns the value of a feature flag or setting based on it's key */
-    getValue(key: string, defaultValue: any, callback: (value: any) => void, user?: User): void;
-    /** Returns the value of a feature flag or setting based on it's key */
-    getValueAsync(key: string, defaultValue: any, user?: User): Promise<any>;
+    getValueAsync<T extends SettingValue>(key: string, defaultValue: T, user?: User): Promise<SettingTypeOf<T>>;
+    /** Returns the value along with evaluation details of a feature flag or setting based on it's key
+     * @deprecated This method is obsolete and will be removed from the public API in a future major version. Please use the getValueDetailsAsync() method instead.
+     */
+    getValueDetails<T extends SettingValue>(key: string, defaultValue: T, callback: (evaluationDetails: IEvaluationDetails<SettingTypeOf<T>>) => void, user?: User): void;
+    /** Returns the value along with evaluation details of a feature flag or setting based on it's key */
+    getValueDetailsAsync<T extends SettingValue>(key: string, defaultValue: T, user?: User): Promise<IEvaluationDetails<SettingTypeOf<T>>>;
+    /** Downloads the latest feature flag and configuration values
+     * @deprecated This method is obsolete and will be removed from the public API in a future major version. Please use the forceRefreshAsync() method instead.
+     */
+    forceRefresh(callback: (result: RefreshResult) => void): void;
     /** Downloads the latest feature flag and configuration values */
-    forceRefresh(callback: () => void): void;
-    /** Downloads the latest feature flag and configuration values */
-    forceRefreshAsync(): Promise<any>;
-    /** Gets a list of keys for all your feature flags and settings */
+    forceRefreshAsync(): Promise<RefreshResult>;
+    /** Gets a list of keys for all your feature flags and settings
+     * @deprecated This method is obsolete and will be removed from the public API in a future major version. Please use the getAllKeysAsync() method instead.
+     */
     getAllKeys(callback: (value: string[]) => void): void;
     /** Gets a list of keys for all your feature flags and settings */
     getAllKeysAsync(): Promise<string[]>;
-    /** Returns the Variation ID (analytics) of a feature flag or setting based on it's key */
-    getVariationId(key: string, defaultVariationId: any, callback: (variationId: string) => void, user?: User): void;
-    /** Returns the Variation ID (analytics) of a feature flag or setting based on it's key */
-    getVariationIdAsync(key: string, defaultVariationId: any, user?: User): Promise<string>;
-    /** Returns the Variation IDs (analytics) of all feature flags or settings */
+    /** Returns the Variation ID (analytics) of a feature flag or setting based on it's key
+     * @deprecated This method is obsolete and will be removed from the public API in a future major version. Please use the getValueDetails() method instead.
+     */
+    getVariationId<T extends VariationIdValue>(key: string, defaultVariationId: T, callback: (variationId: VariationIdTypeOf<T>) => void, user?: User): void;
+    /** Returns the Variation ID (analytics) of a feature flag or setting based on it's key
+     * @deprecated This method is obsolete and will be removed from the public API in a future major version. Please use the getValueDetailsAsync() method instead.
+     */
+    getVariationIdAsync<T extends VariationIdValue>(key: string, defaultVariationId: T, user?: User): Promise<VariationIdTypeOf<T>>;
+    /** Returns the Variation IDs (analytics) of all feature flags or settings
+     * @deprecated This method is obsolete and will be removed from the public API in a future major version. Please use the getAllValueDetails() method instead.
+     */
     getAllVariationIds(callback: (variationIds: string[]) => void, user?: User): void;
-    /** Returns the Variation IDs (analytics) of all feature flags or settings */
+    /** Returns the Variation IDs (analytics) of all feature flags or settings
+     * @deprecated This method is obsolete and will be removed from the public API in a future major version. Please use the getAllValueDetailsAsync() method instead.
+     */
     getAllVariationIdsAsync(user?: User): Promise<string[]>;
-    /** Returns the key of a setting and it's value identified by the given Variation ID (analytics) */
+    /** Returns the key of a setting and it's value identified by the given Variation ID (analytics)
+     * @deprecated This method is obsolete and will be removed from the public API in a future major version. Please use the getKeyAndValueAsync() method instead.
+     */
     getKeyAndValue(variationId: string, callback: (settingkeyAndValue: SettingKeyValue | null) => void): void;
@@ -31,6 +57,14 @@ /** Returns the key of a setting and it's value identified by the given Variation ID (analytics) */
     dispose(): void;
-    /** Returns the values of all feature flags or settings */
+    /** Returns the values of all feature flags or settings
+     * @deprecated This method is obsolete and will be removed from the public API in a future major version. Please use the getAllValuesAsync() method instead.
+     */
     getAllValues(callback: (result: SettingKeyValue[]) => void, user?: User): void;
     /** Returns the values of all feature flags or settings */
     getAllValuesAsync(user?: User): Promise<SettingKeyValue[]>;
+    /** Returns the values along with evaluation details of all feature flags or settings
+     * @deprecated This method is obsolete and will be removed from the public API in a future major version. Please use the getAllValueDetailsAsync() method instead.
+     */
+    getAllValueDetails(callback: (result: IEvaluationDetails[]) => void, user?: User): void;
+    /** Returns the values along with evaluation details of all feature flags or settings */
+    getAllValueDetailsAsync(user?: User): Promise<IEvaluationDetails[]>;
     /** Sets the default user for feature flag evaluations.
@@ -41,4 +75,27 @@ * In case the getValue function isn't called with a UserObject, this default user will be used instead. */
     clearDefaultUser(): void;
+    /** True when the client is configured not to initiate HTTP requests, otherwise false. */
+    get isOffline(): boolean;
+    /** Configures the client to allow HTTP requests. */
+    setOnline(): void;
+    /** Configures the client to not initiate HTTP requests and work only from its cache. */
+    setOffline(): void;
 }
+export interface IConfigCatKernel {
+    configFetcher: IConfigFetcher;
+    /**
+     * Default ICache implementation.
+     */
+    cache?: ICache;
+    sdkType: string;
+    sdkVersion: string;
+    eventEmitterFactory?: () => IEventEmitter;
+}
+export declare class ConfigCatClientCache {
+    private instances;
+    getOrCreate(options: ConfigCatClientOptions, configCatKernel: IConfigCatKernel): [ConfigCatClient, boolean];
+    remove(sdkKey: string, cacheToken: object): boolean;
+    clear(): ConfigCatClient[];
+}
 export declare class ConfigCatClient implements IConfigCatClient {
+    private cacheToken?;
     private configService?;
@@ -48,12 +105,20 @@ private evaluator;
     private defaultUser?;
-    constructor(options: AutoPollOptions | ManualPollOptions | LazyLoadOptions, configCatKernel: IConfigCatKernel);
+    private suppressFinalize;
+    private static get instanceCache();
+    static get<TMode extends PollingMode>(sdkKey: string, pollingMode: TMode, options: OptionsForPollingMode<TMode> | undefined | null, configCatKernel: IConfigCatKernel): IConfigCatClient;
+    constructor(options: ConfigCatClientOptions, configCatKernel: IConfigCatKernel, cacheToken?: object | undefined);
+    private static finalize;
+    private static close;
     dispose(): void;
-    getValue(key: string, defaultValue: any, callback: (value: any) => void, user?: User): void;
-    getValueAsync(key: string, defaultValue: any, user?: User): Promise<any>;
-    forceRefresh(callback: () => void): void;
-    forceRefreshAsync(): Promise<void>;
+    static disposeAll(): void;
+    getValue<T extends SettingValue>(key: string, defaultValue: T, callback: (value: SettingTypeOf<T>) => void, user?: User): void;
+    getValueAsync<T extends SettingValue>(key: string, defaultValue: T, user?: User): Promise<SettingTypeOf<T>>;
+    getValueDetails<T extends SettingValue>(key: string, defaultValue: T, callback: (evaluationDetails: IEvaluationDetails<SettingTypeOf<T>>) => void, user?: User): void;
+    getValueDetailsAsync<T extends SettingValue>(key: string, defaultValue: T, user?: User): Promise<IEvaluationDetails<SettingTypeOf<T>>>;
+    forceRefresh(callback: (result: RefreshResult) => void): void;
+    forceRefreshAsync(): Promise<RefreshResult>;
     getAllKeys(callback: (value: string[]) => void): void;
     getAllKeysAsync(): Promise<string[]>;
-    getVariationId(key: string, defaultVariationId: any, callback: (variationId: string) => void, user?: User): void;
-    getVariationIdAsync(key: string, defaultVariationId: any, user?: User): Promise<string>;
+    getVariationId<T extends VariationIdValue>(key: string, defaultVariationId: T, callback: (variationId: VariationIdTypeOf<T>) => void, user?: User): void;
+    getVariationIdAsync<T extends VariationIdValue>(key: string, defaultVariationId: T, user?: User): Promise<VariationIdTypeOf<T>>;
     getAllVariationIds(callback: (variationIds: string[]) => void, user?: User): void;
@@ -65,10 +130,34 @@ getAllVariationIdsAsync(user?: User): Promise<string[]>;
     getAllValuesAsync(user?: User): Promise<SettingKeyValue[]>;
+    getAllValueDetails(callback: (result: IEvaluationDetails[]) => void, user?: User): void;
+    getAllValueDetailsAsync(user?: User): Promise<IEvaluationDetails[]>;
     setDefaultUser(defaultUser: User): void;
     clearDefaultUser(): void;
+    get isOffline(): boolean;
+    setOnline(): void;
+    setOffline(): void;
     private getSettingsAsync;
+    /** @inheritdoc */
+    addListener: <TEventName extends keyof HookEvents>(eventName: TEventName, listener: (...args: HookEvents[TEventName]) => void) => this;
+    /** @inheritdoc */
+    on<TEventName extends keyof HookEvents>(eventName: TEventName, listener: (...args: HookEvents[TEventName]) => void): this;
+    /** @inheritdoc */
+    once<TEventName extends keyof HookEvents>(eventName: TEventName, listener: (...args: HookEvents[TEventName]) => void): this;
+    /** @inheritdoc */
+    removeListener<TEventName extends keyof HookEvents>(eventName: TEventName, listener: (...args: HookEvents[TEventName]) => void): this;
+    /** @inheritdoc */
+    off: <TEventName extends keyof HookEvents>(eventName: TEventName, listener: (...args: HookEvents[TEventName]) => void) => this;
+    /** @inheritdoc */
+    removeAllListeners(eventName?: keyof HookEvents): this;
+    /** @inheritdoc */
+    listeners(eventName: keyof HookEvents): Function[];
+    /** @inheritdoc */
+    listenerCount(eventName: keyof HookEvents): number;
+    /** @inheritdoc */
+    eventNames(): Array<keyof HookEvents>;
 }
-export declare class SettingKeyValue {
+export declare class SettingKeyValue<TValue = SettingValue> {
     settingKey: string;
-    settingValue: any;
+    settingValue: TValue;
+    constructor(settingKey: string, settingValue: TValue);
 }
 //# sourceMappingURL=ConfigCatClient.d.ts.map

lib/ConfigCatClient.js

 "use strict";
-var __assign = (this && this.__assign) || function () {
-    __assign = Object.assign || function(t) {
-        for (var s, i = 1, n = arguments.length; i < n; i++) {
-            s = arguments[i];
-            for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
-                t[p] = s[p];
-        }
-        return t;
-    };
-    return __assign.apply(this, arguments);
-};
-var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
-    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
-    return new (P || (P = Promise))(function (resolve, reject) {
-        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
-        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
-        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
-        step((generator = generator.apply(thisArg, _arguments || [])).next());
-    });
-};
-var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
-    function verb(n) { return function (v) { return step([n, v]); }; }
-    function step(op) {
-        if (f) throw new TypeError("Generator is already executing.");
-        while (_) try {
-            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
-            if (y = 0, t) op = [op[0] & 2, t.value];
-            switch (op[0]) {
-                case 0: case 1: t = op; break;
-                case 4: _.label++; return { value: op[1], done: false };
-                case 5: _.label++; y = op[1]; op = [0]; continue;
-                case 7: op = _.ops.pop(); _.trys.pop(); continue;
-                default:
-                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
-                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
-                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
-                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
-                    if (t[2]) _.ops.pop();
-                    _.trys.pop(); continue;
-            }
-            op = body.call(thisArg, _);
-        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
-        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
-    }
-};
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.SettingKeyValue = exports.ConfigCatClient = void 0;
+exports.SettingKeyValue = exports.ConfigCatClient = exports.ConfigCatClientCache = void 0;
+var tslib_1 = require("tslib");
+var AutoPollConfigService_1 = require("./AutoPollConfigService");
 var ConfigCatClientOptions_1 = require("./ConfigCatClientOptions");
-var AutoPollConfigService_1 = require("./AutoPollConfigService");
+var ConfigServiceBase_1 = require("./ConfigServiceBase");
+var FlagOverrides_1 = require("./FlagOverrides");
 var LazyLoadConfigService_1 = require("./LazyLoadConfigService");
-var ManualPollService_1 = require("./ManualPollService");
+var ManualPollConfigService_1 = require("./ManualPollConfigService");
+var ProjectConfig_1 = require("./ProjectConfig");
 var RolloutEvaluator_1 = require("./RolloutEvaluator");
-var ProjectConfig_1 = require("./ProjectConfig");
-var FlagOverrides_1 = require("./FlagOverrides");
 var Utils_1 = require("./Utils");
+var ConfigCatClientCache = /** @class */ (function () {
+    function ConfigCatClientCache() {
+        this.instances = {};
+    }
+    ConfigCatClientCache.prototype.getOrCreate = function (options, configCatKernel) {
+        var instance;
+        var cachedInstance = this.instances[options.apiKey];
+        if (cachedInstance) {
+            var weakRef = cachedInstance[0];
+            instance = weakRef.deref();
+            if (instance) {
+                return [instance, true];
+            }
+        }
+        var token = {};
+        instance = new ConfigCatClient(options, configCatKernel, token);
+        this.instances[options.apiKey] = [new WeakRef(instance), token];
+        return [instance, false];
+    };
+    ConfigCatClientCache.prototype.remove = function (sdkKey, cacheToken) {
+        var cachedInstance = this.instances[sdkKey];
+        if (cachedInstance) {
+            var weakRef = cachedInstance[0], token = cachedInstance[1];
+            var instanceIsAvailable = !!weakRef.deref();
+            if (!instanceIsAvailable || token === cacheToken) {
+                delete this.instances[sdkKey];
+                return instanceIsAvailable;
+            }
+        }
+        return false;
+    };
+    ConfigCatClientCache.prototype.clear = function () {
+        var removedInstances = [];
+        for (var _i = 0, _a = Object.entries(this.instances); _i < _a.length; _i++) {
+            var _b = _a[_i], sdkKey = _b[0], weakRef = _b[1][0];
+            var instance = weakRef.deref();
+            if (instance) {
+                removedInstances.push(instance);
+            }
+            delete this.instances[sdkKey];
+        }
+        return removedInstances;
+    };
+    return ConfigCatClientCache;
+}());
+exports.ConfigCatClientCache = ConfigCatClientCache;
+var clientInstanceCache = new ConfigCatClientCache();
 var ConfigCatClient = /** @class */ (function () {
-    function ConfigCatClient(options, configCatKernel) {
+    function ConfigCatClient(options, configCatKernel, cacheToken) {
         var _a;
+        this.cacheToken = cacheToken;
+        /** @inheritdoc */
+        this.addListener = this.on;
+        /** @inheritdoc */
+        this.off = this.removeListener;
         if (!options) {
@@ -73,189 +80,317 @@ throw new Error("Invalid 'options' value");
         }
-        if (options === null || options === void 0 ? void 0 : options.defaultUser) {
+        if (options.defaultUser) {
             this.setDefaultUser(options.defaultUser);
         }
         this.evaluator = new RolloutEvaluator_1.RolloutEvaluator(options.logger);
-        if (((_a = options === null || options === void 0 ? void 0 : options.flagOverrides) === null || _a === void 0 ? void 0 : _a.behaviour) != FlagOverrides_1.OverrideBehaviour.LocalOnly) {
-            if (options && options instanceof ConfigCatClientOptions_1.LazyLoadOptions) {
-                this.configService = new LazyLoadConfigService_1.LazyLoadConfigService(configCatKernel.configFetcher, options);
-            }
-            else if (options && options instanceof ConfigCatClientOptions_1.ManualPollOptions) {
-                this.configService = new ManualPollService_1.ManualPollService(configCatKernel.configFetcher, options);
-            }
-            else if (options && options instanceof ConfigCatClientOptions_1.AutoPollOptions) {
-                this.configService = new AutoPollConfigService_1.AutoPollConfigService(configCatKernel.configFetcher, options);
-            }
-            else {
-                throw new Error("Invalid 'options' value");
-            }
+        if (((_a = options.flagOverrides) === null || _a === void 0 ? void 0 : _a.behaviour) != FlagOverrides_1.OverrideBehaviour.LocalOnly) {
+            var configServiceClass = options instanceof ConfigCatClientOptions_1.AutoPollOptions ? AutoPollConfigService_1.AutoPollConfigService :
+                options instanceof ConfigCatClientOptions_1.ManualPollOptions ? ManualPollConfigService_1.ManualPollConfigService :
+                    options instanceof ConfigCatClientOptions_1.LazyLoadOptions ? LazyLoadConfigService_1.LazyLoadConfigService :
+                        (function () { throw new Error("Invalid 'options' value"); })();
+            this.configService = new configServiceClass(configCatKernel.configFetcher, options);
         }
+        else {
+            this.options.hooks.emit("clientReady");
+        }
+        this.suppressFinalize = registerForFinalization(this, { sdkKey: options.apiKey, cacheToken: cacheToken, configService: this.configService, logger: options.logger });
     }
+    Object.defineProperty(ConfigCatClient, "instanceCache", {
+        get: function () { return clientInstanceCache; },
+        enumerable: false,
+        configurable: true
+    });
+    ;
+    ConfigCatClient.get = function (sdkKey, pollingMode, options, configCatKernel) {
+        if (!sdkKey) {
+            throw new Error("Invalid 'sdkKey' value");
+        }
+        var optionsClass = pollingMode === ConfigCatClientOptions_1.PollingMode.AutoPoll ? ConfigCatClientOptions_1.AutoPollOptions :
+            pollingMode === ConfigCatClientOptions_1.PollingMode.ManualPoll ? ConfigCatClientOptions_1.ManualPollOptions :
+                pollingMode === ConfigCatClientOptions_1.PollingMode.LazyLoad ? ConfigCatClientOptions_1.LazyLoadOptions :
+                    (function () { throw new Error("Invalid 'pollingMode' value"); })();
+        var actualOptions = new optionsClass(sdkKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache, configCatKernel.eventEmitterFactory);
+        var _a = clientInstanceCache.getOrCreate(actualOptions, configCatKernel), instance = _a[0], instanceAlreadyCreated = _a[1];
+        if (instanceAlreadyCreated && options) {
+            actualOptions.logger.warn("Client for SDK key '".concat(sdkKey, "' is already created and will be reused; configuration action is being ignored."));
+        }
+        return instance;
+    };
+    ConfigCatClient.finalize = function (data) {
+        // Safeguard against situations where user forgets to dispose of the client instance.
+        var _a;
+        (_a = data.logger) === null || _a === void 0 ? void 0 : _a.debug("finalize() called");
+        if (data.cacheToken) {
+            clientInstanceCache.remove(data.sdkKey, data.cacheToken);
+        }
+        ConfigCatClient.close(data.configService, data.logger);
+    };
+    ConfigCatClient.close = function (configService, logger, hooks) {
+        logger === null || logger === void 0 ? void 0 : logger.debug("close() called");
+        hooks === null || hooks === void 0 ? void 0 : hooks.tryDisconnect();
+        configService === null || configService === void 0 ? void 0 : configService.dispose();
+    };
     ConfigCatClient.prototype.dispose = function () {
-        this.options.logger.debug("dispose() called");
-        if (this.configService instanceof AutoPollConfigService_1.AutoPollConfigService) {
-            this.options.logger.debug("Disposing AutoPollConfigService");
-            this.configService.dispose();
+        var options = this.options;
+        options.logger.debug("dispose() called");
+        if (this.cacheToken) {
+            clientInstanceCache.remove(options.apiKey, this.cacheToken);
         }
+        ConfigCatClient.close(this.configService, options.logger, options.hooks);
+        this.suppressFinalize();
     };
+    ConfigCatClient.disposeAll = function () {
+        var removedInstances = clientInstanceCache.clear();
+        var errors;
+        for (var _i = 0, removedInstances_1 = removedInstances; _i < removedInstances_1.length; _i++) {
+            var instance = removedInstances_1[_i];
+            try {
+                ConfigCatClient.close(instance.configService, instance.options.logger, instance.options.hooks);
+                instance.suppressFinalize();
+            }
+            catch (err) {
+                errors !== null && errors !== void 0 ? errors : (errors = []);
+                errors.push(err);
+            }
+        }
+        if (errors) {
+            throw typeof AggregateError !== "undefined" ? new AggregateError(errors) : errors.pop();
+        }
+    };
     ConfigCatClient.prototype.getValue = function (key, defaultValue, callback, user) {
         this.options.logger.debug("getValue() called.");
-        this.getValueAsync(key, defaultValue, user).then(function (value) {
-            callback(value);
-        });
+        this.getValueAsync(key, defaultValue, user).then(callback);
     };
     ConfigCatClient.prototype.getValueAsync = function (key, defaultValue, user) {
-        var _this = this;
-        this.options.logger.debug("getValueAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var settings, result;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getSettingsAsync()];
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var value, evaluationDetails, remoteConfig, settings, err_1;
+            var _a;
+            return tslib_1.__generator(this, function (_b) {
+                switch (_b.label) {
+                    case 0:
+                        this.options.logger.debug("getValueAsync() called.");
+                        remoteConfig = null;
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _b.label = 1;
                     case 1:
-                        settings = _a.sent();
-                        if (!settings) {
-                            this.options.logger.error("config.json is not present. Returning default value: '" + defaultValue + "'.");
-                            resolve(defaultValue);
-                            return [2 /*return*/];
-                        }
-                        result = this.evaluator.Evaluate(settings, key, defaultValue, user !== null && user !== void 0 ? user : this.defaultUser).Value;
-                        resolve(result);
-                        return [2 /*return*/];
+                        _b.trys.push([1, 3, , 4]);
+                        (0, RolloutEvaluator_1.ensureAllowedDefaultValue)(defaultValue);
+                        settings = void 0;
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _b.sent(), settings = _a[0], remoteConfig = _a[1];
+                        evaluationDetails = (0, RolloutEvaluator_1.evaluate)(this.evaluator, settings, key, defaultValue, user, remoteConfig, this.options.logger);
+                        value = evaluationDetails.value;
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_1 = _b.sent();
+                        this.options.logger.error("Error occurred in getValueAsync().", err_1);
+                        evaluationDetails = (0, RolloutEvaluator_1.evaluationDetailsFromDefaultValue)(key, defaultValue, (0, Utils_1.getTimestampAsDate)(remoteConfig), user, (0, Utils_1.errorToString)(err_1), err_1);
+                        value = defaultValue;
+                        return [3 /*break*/, 4];
+                    case 4:
+                        this.options.hooks.emit("flagEvaluated", evaluationDetails);
+                        return [2 /*return*/, value];
                 }
             });
-        }); });
+        });
     };
+    ConfigCatClient.prototype.getValueDetails = function (key, defaultValue, callback, user) {
+        this.options.logger.debug("getValueDetails() called.");
+        this.getValueDetailsAsync(key, defaultValue, user).then(callback);
+    };
+    ConfigCatClient.prototype.getValueDetailsAsync = function (key, defaultValue, user) {
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var evaluationDetails, remoteConfig, settings, err_2;
+            var _a;
+            return tslib_1.__generator(this, function (_b) {
+                switch (_b.label) {
+                    case 0:
+                        this.options.logger.debug("getValueDetailsAsync() called.");
+                        remoteConfig = null;
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _b.label = 1;
+                    case 1:
+                        _b.trys.push([1, 3, , 4]);
+                        (0, RolloutEvaluator_1.ensureAllowedDefaultValue)(defaultValue);
+                        settings = void 0;
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _b.sent(), settings = _a[0], remoteConfig = _a[1];
+                        evaluationDetails = (0, RolloutEvaluator_1.evaluate)(this.evaluator, settings, key, defaultValue, user, remoteConfig, this.options.logger);
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_2 = _b.sent();
+                        this.options.logger.error("Error occurred in getValueDetailsAsync().", err_2);
+                        evaluationDetails = (0, RolloutEvaluator_1.evaluationDetailsFromDefaultValue)(key, defaultValue, (0, Utils_1.getTimestampAsDate)(remoteConfig), user, (0, Utils_1.errorToString)(err_2), err_2);
+                        return [3 /*break*/, 4];
+                    case 4:
+                        this.options.hooks.emit("flagEvaluated", evaluationDetails);
+                        return [2 /*return*/, evaluationDetails];
+                }
+            });
+        });
+    };
     ConfigCatClient.prototype.forceRefresh = function (callback) {
         this.options.logger.debug("forceRefresh() called.");
-        this.forceRefreshAsync().then(function () {
-            callback();
-        });
+        this.forceRefreshAsync().then(callback);
     };
     ConfigCatClient.prototype.forceRefreshAsync = function () {
-        var _this = this;
-        this.options.logger.debug("forceRefreshAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var _a;
-            return __generator(this, function (_b) {
-                switch (_b.label) {
-                    case 0: return [4 /*yield*/, ((_a = this.configService) === null || _a === void 0 ? void 0 : _a.refreshConfigAsync())];
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var result, err_3;
+            return tslib_1.__generator(this, function (_a) {
+                switch (_a.label) {
+                    case 0:
+                        this.options.logger.debug("forceRefreshAsync() called.");
+                        if (!this.configService) return [3 /*break*/, 5];
+                        _a.label = 1;
                     case 1:
-                        _b.sent();
-                        resolve();
-                        return [2 /*return*/];
+                        _a.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.configService.refreshConfigAsync()];
+                    case 2:
+                        result = (_a.sent())[0];
+                        return [2 /*return*/, result];
+                    case 3:
+                        err_3 = _a.sent();
+                        this.options.logger.error("Error occurred in forceRefreshAsync().", err_3);
+                        return [2 /*return*/, ConfigServiceBase_1.RefreshResult.failure((0, Utils_1.errorToString)(err_3), err_3)];
+                    case 4: return [3 /*break*/, 6];
+                    case 5: return [2 /*return*/, ConfigServiceBase_1.RefreshResult.failure("Client is configured to use the LocalOnly override behavior, which prevents making HTTP requests.")];
+                    case 6: return [2 /*return*/];
                 }
             });
-        }); });
+        });
     };
     ConfigCatClient.prototype.getAllKeys = function (callback) {
         this.options.logger.debug("getAllKeys() called.");
-        this.getAllKeysAsync().then(function (value) {
-            callback(value);
-        });
+        this.getAllKeysAsync().then(callback);
     };
     ConfigCatClient.prototype.getAllKeysAsync = function () {
-        var _this = this;
-        this.options.logger.debug("getAllKeysAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var settings;
-            return __generator(this, function (_a) {
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var settings, err_4;
+            return tslib_1.__generator(this, function (_a) {
                 switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getSettingsAsync()];
+                    case 0:
+                        this.options.logger.debug("getAllKeysAsync() called.");
+                        _a.label = 1;
                     case 1:
-                        settings = _a.sent();
-                        if (!settings) {
-                            this.options.logger.error("config.json is not present, returning empty array");
-                            resolve([]);
-                            return [2 /*return*/];
+                        _a.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        settings = (_a.sent())[0];
+                        if (!(0, RolloutEvaluator_1.checkSettingsAvailable)(settings, this.options.logger, ", returning empty array")) {
+                            return [2 /*return*/, []];
                         }
-                        resolve(Object.keys(settings));
-                        return [2 /*return*/];
+                        return [2 /*return*/, Object.keys(settings)];
+                    case 3:
+                        err_4 = _a.sent();
+                        this.options.logger.error("Error occurred in getAllKeysAsync().", err_4);
+                        return [2 /*return*/, []];
+                    case 4: return [2 /*return*/];
                 }
             });
-        }); });
+        });
     };
     ConfigCatClient.prototype.getVariationId = function (key, defaultVariationId, callback, user) {
         this.options.logger.debug("getVariationId() called.");
-        this.getVariationIdAsync(key, defaultVariationId, user).then(function (variationId) {
-            callback(variationId);
-        });
+        this.getVariationIdAsync(key, defaultVariationId, user).then(callback);
     };
     ConfigCatClient.prototype.getVariationIdAsync = function (key, defaultVariationId, user) {
-        var _this = this;
-        this.options.logger.debug("getVariationIdAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var settings, result;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getSettingsAsync()];
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var variationId, evaluationDetails, remoteConfig, settings, err_5;
+            var _a;
+            return tslib_1.__generator(this, function (_b) {
+                switch (_b.label) {
+                    case 0:
+                        this.options.logger.debug("getVariationIdAsync() called.");
+                        remoteConfig = null;
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _b.label = 1;
                     case 1:
-                        settings = _a.sent();
-                        if (!settings) {
-                            this.options.logger.error("config.json is not present. Returning default variationId: '" + defaultVariationId + "'.");
-                            resolve(defaultVariationId);
-                            return [2 /*return*/];
-                        }
-                        result = this.evaluator.Evaluate(settings, key, null, user !== null && user !== void 0 ? user : this.defaultUser, defaultVariationId).VariationId;
-                        resolve(result);
-                        return [2 /*return*/];
+                        _b.trys.push([1, 3, , 4]);
+                        settings = void 0;
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _b.sent(), settings = _a[0], remoteConfig = _a[1];
+                        evaluationDetails = (0, RolloutEvaluator_1.evaluateVariationId)(this.evaluator, settings, key, defaultVariationId, user, remoteConfig, this.options.logger);
+                        variationId = evaluationDetails.variationId;
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_5 = _b.sent();
+                        this.options.logger.error("Error occurred in getVariationIdAsync().", err_5);
+                        evaluationDetails = (0, RolloutEvaluator_1.evaluationDetailsFromDefaultVariationId)(key, defaultVariationId, (0, Utils_1.getTimestampAsDate)(remoteConfig), user, (0, Utils_1.errorToString)(err_5), err_5);
+                        variationId = defaultVariationId;
+                        return [3 /*break*/, 4];
+                    case 4:
+                        this.options.hooks.emit("flagEvaluated", evaluationDetails);
+                        return [2 /*return*/, variationId];
                 }
             });
-        }); });
+        });
     };
     ConfigCatClient.prototype.getAllVariationIds = function (callback, user) {
         this.options.logger.debug("getAllVariationIds() called.");
-        this.getAllVariationIdsAsync(user).then(function (variationIds) {
-            callback(variationIds);
-        });
+        this.getAllVariationIdsAsync(user).then(callback);
     };
     ConfigCatClient.prototype.getAllVariationIdsAsync = function (user) {
-        var _this = this;
-        this.options.logger.debug("getAllVariationIdsAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var keys, promises, variationIds;
-            var _this = this;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getAllKeysAsync()];
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var result, evaluationDetailsArray, _a, settings, remoteConfig, errors, err_6, _i, evaluationDetailsArray_1, evaluationDetail;
+            var _b;
+            return tslib_1.__generator(this, function (_c) {
+                switch (_c.label) {
+                    case 0:
+                        this.options.logger.debug("getAllVariationIdsAsync() called.");
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _c.label = 1;
                     case 1:
-                        keys = _a.sent();
-                        if (keys.length === 0) {
-                            resolve([]);
-                            return [2 /*return*/];
+                        _c.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _c.sent(), settings = _a[0], remoteConfig = _a[1];
+                        errors = void 0;
+                        _b = (0, RolloutEvaluator_1.evaluateAllVariationIds)(this.evaluator, settings, user, remoteConfig, this.options.logger), evaluationDetailsArray = _b[0], errors = _b[1];
+                        if (errors === null || errors === void 0 ? void 0 : errors.length) {
+                            throw typeof AggregateError !== "undefined" ? new AggregateError(errors) : errors.pop();
                         }
-                        promises = keys.map(function (key) { return _this.getVariationIdAsync(key, null, user); });
-                        return [4 /*yield*/, Promise.all(promises)];
-                    case 2:
-                        variationIds = _a.sent();
-                        resolve(variationIds);
-                        return [2 /*return*/];
+                        result = evaluationDetailsArray.filter(function (details) { return details !== null && details !== void 0; }).map(function (details) { return details.variationId; });
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_6 = _c.sent();
+                        this.options.logger.error("Error occurred in getAllVariationIdsAsync().", err_6);
+                        evaluationDetailsArray !== null && evaluationDetailsArray !== void 0 ? evaluationDetailsArray : (evaluationDetailsArray = []);
+                        result = [];
+                        return [3 /*break*/, 4];
+                    case 4:
+                        for (_i = 0, evaluationDetailsArray_1 = evaluationDetailsArray; _i < evaluationDetailsArray_1.length; _i++) {
+                            evaluationDetail = evaluationDetailsArray_1[_i];
+                            this.options.hooks.emit("flagEvaluated", evaluationDetail);
+                        }
+                        return [2 /*return*/, result];
                 }
             });
-        }); });
+        });
     };
     ConfigCatClient.prototype.getKeyAndValue = function (variationId, callback) {
         this.options.logger.debug("getKeyAndValue() called.");
-        this.getKeyAndValueAsync(variationId).then(function (settingKeyAndValue) {
-            callback(settingKeyAndValue);
-        });
+        this.getKeyAndValueAsync(variationId).then(callback);
     };
     ConfigCatClient.prototype.getKeyAndValueAsync = function (variationId) {
-        var _this = this;
-        this.options.logger.debug("getKeyAndValueAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var settings, settingKey, rolloutRules, i, rolloutRule, percentageItems, i, percentageItem;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getSettingsAsync()];
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var settings, _i, _a, _b, settingKey, setting, rolloutRules, i, rolloutRule, percentageItems, i, percentageItem, err_7;
+            return tslib_1.__generator(this, function (_c) {
+                switch (_c.label) {
+                    case 0:
+                        this.options.logger.debug("getKeyAndValueAsync() called.");
+                        _c.label = 1;
                     case 1:
-                        settings = _a.sent();
-                        if (!settings) {
-                            this.options.logger.error("config.json is not present, returning empty array");
-                            resolve(null);
-                            return [2 /*return*/];
+                        _c.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        settings = (_c.sent())[0];
+                        if (!(0, RolloutEvaluator_1.checkSettingsAvailable)(settings, this.options.logger, ", returning null")) {
+                            return [2 /*return*/, null];
                         }
-                        for (settingKey in settings) {
-                            if (variationId === settings[settingKey].variationId) {
-                                resolve({ settingKey: settingKey, settingValue: settings[settingKey].value });
-                                return [2 /*return*/];
+                        for (_i = 0, _a = Object.entries(settings); _i < _a.length; _i++) {
+                            _b = _a[_i], settingKey = _b[0], setting = _b[1];
+                            if (variationId === setting.variationId) {
+                                return [2 /*return*/, new SettingKeyValue(settingKey, setting.value)];
                             }
@@ -267,4 +402,3 @@ rolloutRules = settings[settingKey].rolloutRules;
                                     if (variationId === rolloutRule.variationId) {
-                                        resolve({ settingKey: settingKey, settingValue: rolloutRule.value });
-                                        return [2 /*return*/];
+                                        return [2 /*return*/, new SettingKeyValue(settingKey, rolloutRule.value)];
                                     }
@@ -278,4 +412,3 @@ }
                                     if (variationId === percentageItem.variationId) {
-                                        resolve({ settingKey: settingKey, settingValue: percentageItem.value });
-                                        return [2 /*return*/];
+                                        return [2 /*return*/, new SettingKeyValue(settingKey, percentageItem.value)];
                                     }
@@ -286,44 +419,94 @@ }
                         this.options.logger.error("Could not find the setting for the given variation ID: " + variationId);
-                        resolve(null);
-                        return [2 /*return*/];
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_7 = _c.sent();
+                        this.options.logger.error("Error occurred in getKeyAndValueAsync().", err_7);
+                        return [3 /*break*/, 4];
+                    case 4: return [2 /*return*/, null];
                 }
             });
-        }); });
+        });
     };
     ConfigCatClient.prototype.getAllValues = function (callback, user) {
         this.options.logger.debug("getAllValues() called.");
-        this.getAllValuesAsync(user).then(function (value) {
-            callback(value);
-        });
+        this.getAllValuesAsync(user).then(callback);
     };
     ConfigCatClient.prototype.getAllValuesAsync = function (user) {
-        var _this = this;
-        this.options.logger.debug("getAllValuesAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var settings, keys, result;
-            var _this = this;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getSettingsAsync()];
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var result, evaluationDetailsArray, _a, settings, remoteConfig, errors, err_8, _i, evaluationDetailsArray_2, evaluationDetail;
+            var _b;
+            return tslib_1.__generator(this, function (_c) {
+                switch (_c.label) {
+                    case 0:
+                        this.options.logger.debug("getAllValuesAsync() called.");
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _c.label = 1;
                     case 1:
-                        settings = _a.sent();
-                        if (!settings) {
-                            this.options.logger.error("config.json is not present, returning empty array");
-                            resolve([]);
-                            return [2 /*return*/];
+                        _c.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _c.sent(), settings = _a[0], remoteConfig = _a[1];
+                        errors = void 0;
+                        _b = (0, RolloutEvaluator_1.evaluateAll)(this.evaluator, settings, user, remoteConfig, this.options.logger), evaluationDetailsArray = _b[0], errors = _b[1];
+                        if (errors === null || errors === void 0 ? void 0 : errors.length) {
+                            throw typeof AggregateError !== "undefined" ? new AggregateError(errors) : errors.pop();
                         }
-                        keys = Object.keys(settings);
+                        result = evaluationDetailsArray.map(function (details) { return new SettingKeyValue(details.key, details.value); });
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_8 = _c.sent();
+                        this.options.logger.error("Error occurred in getAllValuesAsync().", err_8);
+                        evaluationDetailsArray !== null && evaluationDetailsArray !== void 0 ? evaluationDetailsArray : (evaluationDetailsArray = []);
                         result = [];
-                        keys.forEach(function (key) {
-                            result.push({
-                                settingKey: key,
-                                settingValue: _this.evaluator.Evaluate(settings, key, undefined, user !== null && user !== void 0 ? user : _this.defaultUser).Value
-                            });
-                        });
-                        resolve(result);
-                        return [2 /*return*/];
+                        return [3 /*break*/, 4];
+                    case 4:
+                        for (_i = 0, evaluationDetailsArray_2 = evaluationDetailsArray; _i < evaluationDetailsArray_2.length; _i++) {
+                            evaluationDetail = evaluationDetailsArray_2[_i];
+                            this.options.hooks.emit("flagEvaluated", evaluationDetail);
+                        }
+                        return [2 /*return*/, result];
                 }
             });
-        }); });
+        });
     };
+    ConfigCatClient.prototype.getAllValueDetails = function (callback, user) {
+        this.options.logger.debug("getAllValueDetails() called.");
+        this.getAllValueDetailsAsync(user).then(callback);
+    };
+    ConfigCatClient.prototype.getAllValueDetailsAsync = function (user) {
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var evaluationDetailsArray, _a, settings, remoteConfig, errors, err_9, _i, evaluationDetailsArray_3, evaluationDetail;
+            var _b;
+            return tslib_1.__generator(this, function (_c) {
+                switch (_c.label) {
+                    case 0:
+                        this.options.logger.debug("getAllValueDetailsAsync() called.");
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _c.label = 1;
+                    case 1:
+                        _c.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _c.sent(), settings = _a[0], remoteConfig = _a[1];
+                        errors = void 0;
+                        _b = (0, RolloutEvaluator_1.evaluateAll)(this.evaluator, settings, user, remoteConfig, this.options.logger), evaluationDetailsArray = _b[0], errors = _b[1];
+                        if (errors === null || errors === void 0 ? void 0 : errors.length) {
+                            throw typeof AggregateError !== "undefined" ? new AggregateError(errors) : errors.pop();
+                        }
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_9 = _c.sent();
+                        this.options.logger.error("Error occurred in getAllValueDetailsAsync().", err_9);
+                        evaluationDetailsArray !== null && evaluationDetailsArray !== void 0 ? evaluationDetailsArray : (evaluationDetailsArray = []);
+                        return [3 /*break*/, 4];
+                    case 4:
+                        for (_i = 0, evaluationDetailsArray_3 = evaluationDetailsArray; _i < evaluationDetailsArray_3.length; _i++) {
+                            evaluationDetail = evaluationDetailsArray_3[_i];
+                            this.options.hooks.emit("flagEvaluated", evaluationDetail);
+                        }
+                        return [2 /*return*/, evaluationDetailsArray];
+                }
+            });
+        });
+    };
     ConfigCatClient.prototype.setDefaultUser = function (defaultUser) {
@@ -333,47 +516,109 @@ this.defaultUser = defaultUser;
     ConfigCatClient.prototype.clearDefaultUser = function () {
-        this.defaultUser = undefined;
+        this.defaultUser = void 0;
     };
+    Object.defineProperty(ConfigCatClient.prototype, "isOffline", {
+        get: function () {
+            var _a, _b;
+            return (_b = (_a = this.configService) === null || _a === void 0 ? void 0 : _a.isOffline) !== null && _b !== void 0 ? _b : true;
+        },
+        enumerable: false,
+        configurable: true
+    });
+    ConfigCatClient.prototype.setOnline = function () {
+        if (this.configService) {
+            this.configService.setOnline();
+        }
+        else {
+            this.options.logger.warn("Client is configured to use the LocalOnly override behavior, thus SetOnline() has no effect.");
+        }
+    };
+    ConfigCatClient.prototype.setOffline = function () {
+        var _a;
+        (_a = this.configService) === null || _a === void 0 ? void 0 : _a.setOffline();
+    };
     ConfigCatClient.prototype.getSettingsAsync = function () {
-        var _this = this;
-        this.options.logger.debug("getSettingsAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var localSettings, remoteConfig, remoteSettings, config;
-            var _a, _b, _c;
-            return __generator(this, function (_d) {
-                switch (_d.label) {
+        var _a;
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var getRemoteConfigAsync, flagOverrides, remoteSettings, remoteConfig, localSettings, _b;
+            var _c, _d;
+            var _this = this;
+            return tslib_1.__generator(this, function (_e) {
+                switch (_e.label) {
                     case 0:
-                        if (!((_a = this.options) === null || _a === void 0 ? void 0 : _a.flagOverrides)) return [3 /*break*/, 3];
-                        return [4 /*yield*/, this.options.flagOverrides.dataSource.getOverrides()];
+                        this.options.logger.debug("getSettingsAsync() called.");
+                        getRemoteConfigAsync = function () { return tslib_1.__awaiter(_this, void 0, void 0, function () {
+                            var config, json, settings;
+                            var _a;
+                            return tslib_1.__generator(this, function (_b) {
+                                switch (_b.label) {
+                                    case 0: return [4 /*yield*/, ((_a = this.configService) === null || _a === void 0 ? void 0 : _a.getConfig())];
+                                    case 1:
+                                        config = _b.sent();
+                                        json = config === null || config === void 0 ? void 0 : config.ConfigJSON;
+                                        settings = (json === null || json === void 0 ? void 0 : json[ProjectConfig_1.ConfigFile.FeatureFlags]) ? (0, Utils_1.getSettingsFromConfig)(json) : null;
+                                        return [2 /*return*/, [settings, config !== null && config !== void 0 ? config : null]];
+                                }
+                            });
+                        }); };
+                        flagOverrides = (_a = this.options) === null || _a === void 0 ? void 0 : _a.flagOverrides;
+                        if (!flagOverrides) return [3 /*break*/, 7];
+                        remoteSettings = void 0;
+                        remoteConfig = void 0;
+                        return [4 /*yield*/, flagOverrides.dataSource.getOverrides()];
                     case 1:
-                        localSettings = _d.sent();
-                        if (this.options.flagOverrides.behaviour == FlagOverrides_1.OverrideBehaviour.LocalOnly) {
-                            resolve(localSettings);
-                            return [2 /*return*/];
+                        localSettings = _e.sent();
+                        _b = flagOverrides.behaviour;
+                        switch (_b) {
+                            case FlagOverrides_1.OverrideBehaviour.LocalOnly: return [3 /*break*/, 2];
+                            case FlagOverrides_1.OverrideBehaviour.LocalOverRemote: return [3 /*break*/, 3];
+                            case FlagOverrides_1.OverrideBehaviour.RemoteOverLocal: return [3 /*break*/, 5];
                         }
-                        return [4 /*yield*/, ((_b = this.configService) === null || _b === void 0 ? void 0 : _b.getConfig())];
-                    case 2:
-                        remoteConfig = _d.sent();
-                        remoteSettings = (0, Utils_1.getSettingsFromConfig)(remoteConfig === null || remoteConfig === void 0 ? void 0 : remoteConfig.ConfigJSON);
-                        if (this.options.flagOverrides.behaviour == FlagOverrides_1.OverrideBehaviour.LocalOverRemote) {
-                            resolve(__assign(__assign({}, remoteSettings), localSettings));
-                            return [2 /*return*/];
-                        }
-                        else if (this.options.flagOverrides.behaviour == FlagOverrides_1.OverrideBehaviour.RemoteOverLocal) {
-                            resolve(__assign(__assign({}, localSettings), remoteSettings));
-                            return [2 /*return*/];
-                        }
-                        _d.label = 3;
-                    case 3: return [4 /*yield*/, ((_c = this.configService) === null || _c === void 0 ? void 0 : _c.getConfig())];
+                        return [3 /*break*/, 7];
+                    case 2: return [2 /*return*/, [localSettings, null]];
+                    case 3: return [4 /*yield*/, getRemoteConfigAsync()];
                     case 4:
-                        config = _d.sent();
-                        if (!config || !config.ConfigJSON || !config.ConfigJSON[ProjectConfig_1.ConfigFile.FeatureFlags]) {
-                            resolve(null);
-                            return [2 /*return*/];
-                        }
-                        resolve((0, Utils_1.getSettingsFromConfig)(config.ConfigJSON));
-                        return [2 /*return*/];
+                        _c = _e.sent(), remoteSettings = _c[0], remoteConfig = _c[1];
+                        return [2 /*return*/, [tslib_1.__assign(tslib_1.__assign({}, (remoteSettings !== null && remoteSettings !== void 0 ? remoteSettings : {})), localSettings), remoteConfig]];
+                    case 5: return [4 /*yield*/, getRemoteConfigAsync()];
+                    case 6:
+                        _d = _e.sent(), remoteSettings = _d[0], remoteConfig = _d[1];
+                        return [2 /*return*/, [tslib_1.__assign(tslib_1.__assign({}, localSettings), (remoteSettings !== null && remoteSettings !== void 0 ? remoteSettings : {})), remoteConfig]];
+                    case 7: return [4 /*yield*/, getRemoteConfigAsync()];
+                    case 8: return [2 /*return*/, _e.sent()];
                 }
             });
-        }); });
+        });
     };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.on = function (eventName, listener) {
+        this.options.hooks.on(eventName, listener);
+        return this;
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.once = function (eventName, listener) {
+        this.options.hooks.once(eventName, listener);
+        return this;
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.removeListener = function (eventName, listener) {
+        this.options.hooks.removeListener(eventName, listener);
+        return this;
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.removeAllListeners = function (eventName) {
+        this.options.hooks.removeAllListeners(eventName);
+        return this;
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.listeners = function (eventName) {
+        return this.options.hooks.listeners(eventName);
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.listenerCount = function (eventName) {
+        return this.options.hooks.listenerCount(eventName);
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.eventNames = function () {
+        return this.options.hooks.eventNames();
+    };
     return ConfigCatClient;
@@ -383,3 +628,5 @@ }());
 var SettingKeyValue = /** @class */ (function () {
-    function SettingKeyValue() {
+    function SettingKeyValue(settingKey, settingValue) {
+        this.settingKey = settingKey;
+        this.settingValue = settingValue;
     }
@@ -389,1 +636,22 @@ return SettingKeyValue;
 exports.SettingKeyValue = SettingKeyValue;
+;
+var registerForFinalization = function (client, data) {
+    // Use FinalizationRegistry (finalization callbacks) if the runtime provides that feature.
+    if (typeof FinalizationRegistry !== "undefined") {
+        var finalizationRegistry_1 = new FinalizationRegistry(function (data) { return ConfigCatClient["finalize"](data); });
+        registerForFinalization = function (client, data) {
+            var unregisterToken = {};
+            finalizationRegistry_1.register(client, data, unregisterToken);
+            return function () { return finalizationRegistry_1.unregister(unregisterToken); };
+        };
+    }
+    // If FinalizationRegistry is unavailable, we can't really track finalization.
+    // (Although we could implement something which resembles finalization callbacks using a weak map + a timer,
+    // since ConfigCatClientCache also needs to keep (weak) references to the created client instances,
+    // this hypothetical approach wouldn't work without a complete WeakRef polyfill,
+    // which is kind of impossible (for more details, see Polyfills.ts).
+    else {
+        registerForFinalization = function () { return function () { }; };
+    }
+    return registerForFinalization(client, data);
+};

lib/ConfigCatClientOptions.d.ts

@@ -1,3 +0,12 @@
-import { IConfigCatLogger, IAutoPollOptions, ILazyLoadingOptions, IManualPollOptions, ICache, User } from "./index";
+import { ICache } from "./Cache";
+import { IConfigCatLogger, LoggerWrapper } from "./ConfigCatLogger";
+import type { IEventEmitter } from "./EventEmitter";
 import { FlagOverrides } from "./FlagOverrides";
+import { Hooks, IProvidesHooks } from "./Hooks";
+import { User } from "./RolloutEvaluator";
+export declare enum PollingMode {
+    AutoPoll = 0,
+    LazyLoad = 1,
+    ManualPoll = 2
+}
 /** Control the location of the config.json files containing your feature flags and settings within the ConfigCat CDN. */
@@ -29,6 +38,23 @@ export declare enum DataGovernance {
     defaultUser?: User | null;
+    /**
+     * Indicates whether the client should be initialized to offline mode or not. Defaults to false.
+     */
+    offline?: boolean | null;
+    /** Provides an opportunity to add listeners to client hooks (events) at client initalization time. */
+    setupHooks?: (hooks: IProvidesHooks) => void;
 }
+export interface IAutoPollOptions extends IOptions {
+    pollIntervalSeconds?: number;
+    maxInitWaitTimeSeconds?: number;
+    configChanged?: () => void;
+}
+export interface IManualPollOptions extends IOptions {
+}
+export interface ILazyLoadingOptions extends IOptions {
+    cacheTimeToLiveSeconds?: number;
+}
+export type OptionsForPollingMode<TMode extends PollingMode> = TMode extends PollingMode.AutoPoll ? IAutoPollOptions : TMode extends PollingMode.ManualPoll ? IManualPollOptions : TMode extends PollingMode.LazyLoad ? ILazyLoadingOptions : never;
 export declare abstract class OptionsBase implements IOptions {
     private configFileName;
-    logger: IConfigCatLogger;
+    logger: LoggerWrapper;
     apiKey: string;
@@ -43,4 +69,6 @@ clientVersion: string;
     flagOverrides?: FlagOverrides;
-    defaultUser?: User | null;
-    constructor(apiKey: string, clientVersion: string, options?: IOptions | null, defaultCache?: ICache | null);
+    defaultUser?: User;
+    offline: boolean;
+    hooks: Hooks;
+    constructor(apiKey: string, clientVersion: string, options?: IOptions | null, defaultCache?: ICache | null, eventEmitterFactory?: (() => IEventEmitter) | null);
     getUrl(): string;
@@ -52,10 +80,12 @@ getCacheKey(): string;
     pollIntervalSeconds: number;
-    /** You can subscribe to configuration changes with this callback. */
+    /** You can subscribe to configuration changes with this callback.
+     * @deprecated This property is obsolete and will be removed from the public API in a future major version. Please use the 'options.setupHooks = hooks => hooks.on("configChanged", ...)' format instead.
+    */
     configChanged: () => void;
     /** Maximum waiting time between the client initialization and the first config acquisition in seconds. */
     maxInitWaitTimeSeconds: number;
-    constructor(apiKey: string, sdkType: string, sdkVersion: string, options?: IAutoPollOptions | null, defaultCache?: ICache | null);
+    constructor(apiKey: string, sdkType: string, sdkVersion: string, options?: IAutoPollOptions | null, defaultCache?: ICache | null, eventEmitterFactory?: (() => IEventEmitter) | null);
 }
 export declare class ManualPollOptions extends OptionsBase implements IManualPollOptions {
-    constructor(apiKey: string, sdkType: string, sdkVersion: string, options?: IManualPollOptions | null, defaultCache?: ICache | null);
+    constructor(apiKey: string, sdkType: string, sdkVersion: string, options?: IManualPollOptions | null, defaultCache?: ICache | null, eventEmitterFactory?: (() => IEventEmitter) | null);
 }
@@ -65,4 +95,5 @@ export declare class LazyLoadOptions extends OptionsBase implements ILazyLoadingOptions {
     cacheTimeToLiveSeconds: number;
-    constructor(apiKey: string, sdkType: string, sdkVersion: string, options?: ILazyLoadingOptions | null, defaultCache?: ICache | null);
+    constructor(apiKey: string, sdkType: string, sdkVersion: string, options?: ILazyLoadingOptions | null, defaultCache?: ICache | null, eventEmitterFactory?: (() => IEventEmitter) | null);
 }
+export type ConfigCatClientOptions = AutoPollOptions | ManualPollOptions | LazyLoadOptions;
 //# sourceMappingURL=ConfigCatClientOptions.d.ts.map

lib/ConfigCatClientOptions.js

 "use strict";
-var __extends = (this && this.__extends) || (function () {
-    var extendStatics = function (d, b) {
-        extendStatics = Object.setPrototypeOf ||
-            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
-            function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
-        return extendStatics(d, b);
-    };
-    return function (d, b) {
-        if (typeof b !== "function" && b !== null)
-            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
-        extendStatics(d, b);
-        function __() { this.constructor = d; }
-        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
-    };
-})();
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.LazyLoadOptions = exports.ManualPollOptions = exports.AutoPollOptions = exports.OptionsBase = exports.DataGovernance = void 0;
+exports.LazyLoadOptions = exports.ManualPollOptions = exports.AutoPollOptions = exports.OptionsBase = exports.DataGovernance = exports.PollingMode = void 0;
+var tslib_1 = require("tslib");
+var Cache_1 = require("./Cache");
 var ConfigCatLogger_1 = require("./ConfigCatLogger");
-var index_1 = require("./index");
-var Cache_1 = require("./Cache");
+var DefaultEventEmitter_1 = require("./DefaultEventEmitter");
+var Hooks_1 = require("./Hooks");
+var PollingMode;
+(function (PollingMode) {
+    PollingMode[PollingMode["AutoPoll"] = 0] = "AutoPoll";
+    PollingMode[PollingMode["LazyLoad"] = 1] = "LazyLoad";
+    PollingMode[PollingMode["ManualPoll"] = 2] = "ManualPoll";
+})(PollingMode = exports.PollingMode || (exports.PollingMode = {}));
 /** Control the location of the config.json files containing your feature flags and settings within the ConfigCat CDN. */
@@ -31,9 +24,9 @@ var DataGovernance;
 var OptionsBase = /** @class */ (function () {
-    function OptionsBase(apiKey, clientVersion, options, defaultCache) {
-        var _a;
+    function OptionsBase(apiKey, clientVersion, options, defaultCache, eventEmitterFactory) {
+        var _a, _b, _c;
         this.configFileName = "config_v5";
-        this.logger = new ConfigCatLogger_1.ConfigCatConsoleLogger(index_1.LogLevel.Warn);
         this.requestTimeoutMs = 30000;
         this.baseUrlOverriden = false;
         this.proxy = "";
+        this.offline = false;
         if (!apiKey) {
@@ -57,6 +50,7 @@ throw new Error("Invalid 'apiKey' value");
         }
+        var eventEmitter = (_b = eventEmitterFactory === null || eventEmitterFactory === void 0 ? void 0 : eventEmitterFactory()) !== null && _b !== void 0 ? _b : new DefaultEventEmitter_1.DefaultEventEmitter();
+        this.hooks = new Hooks_1.Hooks(eventEmitter);
+        var logger;
         if (options) {
-            if (options.logger) {
-                this.logger = options.logger;
-            }
+            logger = options.logger;
             if (options.requestTimeoutMs) {
@@ -84,3 +78,8 @@ if (options.requestTimeoutMs < 0) {
             }
+            if (options.offline) {
+                this.offline = options.offline;
+            }
+            (_c = options.setupHooks) === null || _c === void 0 ? void 0 : _c.call(options, this.hooks);
         }
+        this.logger = new ConfigCatLogger_1.LoggerWrapper(logger !== null && logger !== void 0 ? logger : new ConfigCatLogger_1.ConfigCatConsoleLogger(), this.hooks);
     }
@@ -97,8 +96,10 @@ OptionsBase.prototype.getUrl = function () {
 var AutoPollOptions = /** @class */ (function (_super) {
-    __extends(AutoPollOptions, _super);
-    function AutoPollOptions(apiKey, sdkType, sdkVersion, options, defaultCache) {
-        var _this = _super.call(this, apiKey, sdkType + "/a-" + sdkVersion, options, defaultCache) || this;
+    tslib_1.__extends(AutoPollOptions, _super);
+    function AutoPollOptions(apiKey, sdkType, sdkVersion, options, defaultCache, eventEmitterFactory) {
+        var _this = _super.call(this, apiKey, sdkType + "/a-" + sdkVersion, options, defaultCache, eventEmitterFactory) || this;
         /** The client's poll interval in seconds. Default: 60 seconds. */
         _this.pollIntervalSeconds = 60;
-        /** You can subscribe to configuration changes with this callback. */
+        /** You can subscribe to configuration changes with this callback.
+         * @deprecated This property is obsolete and will be removed from the public API in a future major version. Please use the 'options.setupHooks = hooks => hooks.on("configChanged", ...)' format instead.
+        */
         _this.configChanged = function () { };
@@ -108,3 +109,3 @@ /** Maximum waiting time between the client initialization and the first config acquisition in seconds. */
         if (options) {
-            if (options.pollIntervalSeconds !== undefined && options.pollIntervalSeconds !== null) {
+            if (options.pollIntervalSeconds !== void 0 && options.pollIntervalSeconds !== null) {
                 _this.pollIntervalSeconds = options.pollIntervalSeconds;
@@ -115,10 +116,10 @@ }
             }
-            if (options.maxInitWaitTimeSeconds !== undefined && options.maxInitWaitTimeSeconds !== null) {
+            if (options.maxInitWaitTimeSeconds !== void 0 && options.maxInitWaitTimeSeconds !== null) {
                 _this.maxInitWaitTimeSeconds = options.maxInitWaitTimeSeconds;
             }
         }
-        if (_this.pollIntervalSeconds < 1) {
+        if (!(_this.pollIntervalSeconds >= 1 && (typeof _this.pollIntervalSeconds === 'number'))) {
             throw new Error("Invalid 'pollIntervalSeconds' value");
         }
-        if (_this.maxInitWaitTimeSeconds < 0) {
+        if (!(_this.maxInitWaitTimeSeconds >= 0 && (typeof _this.maxInitWaitTimeSeconds === 'number'))) {
             throw new Error("Invalid 'maxInitWaitTimeSeconds' value");
@@ -132,5 +133,5 @@ }
 var ManualPollOptions = /** @class */ (function (_super) {
-    __extends(ManualPollOptions, _super);
-    function ManualPollOptions(apiKey, sdkType, sdkVersion, options, defaultCache) {
-        return _super.call(this, apiKey, sdkType + "/m-" + sdkVersion, options, defaultCache) || this;
+    tslib_1.__extends(ManualPollOptions, _super);
+    function ManualPollOptions(apiKey, sdkType, sdkVersion, options, defaultCache, eventEmitterFactory) {
+        return _super.call(this, apiKey, sdkType + "/m-" + sdkVersion, options, defaultCache, eventEmitterFactory) || this;
     }
@@ -141,5 +142,5 @@ return ManualPollOptions;
 var LazyLoadOptions = /** @class */ (function (_super) {
-    __extends(LazyLoadOptions, _super);
-    function LazyLoadOptions(apiKey, sdkType, sdkVersion, options, defaultCache) {
-        var _this = _super.call(this, apiKey, sdkType + "/l-" + sdkVersion, options, defaultCache) || this;
+    tslib_1.__extends(LazyLoadOptions, _super);
+    function LazyLoadOptions(apiKey, sdkType, sdkVersion, options, defaultCache, eventEmitterFactory) {
+        var _this = _super.call(this, apiKey, sdkType + "/l-" + sdkVersion, options, defaultCache, eventEmitterFactory) || this;
         /** The cache TTL. */
@@ -146,0 +147,0 @@ _this.cacheTimeToLiveSeconds = 60;

lib/ConfigCatLogger.d.ts

@@ -1,19 +0,50 @@
-import { IConfigCatLogger, LogLevel } from "./index";
+import { Hooks } from "./Hooks";
+export declare enum LogLevel {
+    Debug = 4,
+    Info = 3,
+    Warn = 2,
+    Error = 1,
+    Off = -1
+}
+export interface IConfigCatLogger {
+    readonly level?: LogLevel;
+    debug(message: string): void;
+    /**
+     * @deprecated Use `debug(message: string)` method instead of this
+     */
+    log(message: string): void;
+    info(message: string): void;
+    warn(message: string): void;
+    error(message: string): void;
+}
+export declare class LoggerWrapper implements IConfigCatLogger {
+    private logger;
+    private hooks?;
+    get level(): LogLevel;
+    constructor(logger: IConfigCatLogger, hooks?: Hooks | undefined);
+    log(message: string): void;
+    debug(message: string): void;
+    info(message: string): void;
+    warn(message: string): void;
+    error(message: string, err?: any): void;
+    private isLogLevelEnabled;
+}
 export declare class ConfigCatConsoleLogger implements IConfigCatLogger {
+    level: LogLevel;
     SOURCE: string;
-    level: LogLevel;
     /**
      * Create an instance of ConfigCatConsoleLogger
      */
-    constructor(logLevel: LogLevel);
-    /**
-     * @deprecated Use `debug(message: string)` method instead of this
-     */
+    constructor(level?: LogLevel);
+    /** @inheritdoc */
     log(message: string): void;
+    /** @inheritdoc */
     debug(message: string): void;
+    /** @inheritdoc */
     info(message: string): void;
+    /** @inheritdoc */
     warn(message: string): void;
+    /** @inheritdoc */
     error(message: string): void;
-    isLogLevelEnabled(logLevel: LogLevel): boolean;
 }
 //# sourceMappingURL=ConfigCatLogger.d.ts.map

lib/ConfigCatLogger.js

 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.ConfigCatConsoleLogger = void 0;
-var index_1 = require("./index");
+exports.ConfigCatConsoleLogger = exports.LoggerWrapper = exports.LogLevel = void 0;
+var Utils_1 = require("./Utils");
+var LogLevel;
+(function (LogLevel) {
+    LogLevel[LogLevel["Debug"] = 4] = "Debug";
+    LogLevel[LogLevel["Info"] = 3] = "Info";
+    LogLevel[LogLevel["Warn"] = 2] = "Warn";
+    LogLevel[LogLevel["Error"] = 1] = "Error";
+    LogLevel[LogLevel["Off"] = -1] = "Off";
+})(LogLevel = exports.LogLevel || (exports.LogLevel = {}));
+var LoggerWrapper = /** @class */ (function () {
+    function LoggerWrapper(logger, hooks) {
+        this.logger = logger;
+        this.hooks = hooks;
+    }
+    Object.defineProperty(LoggerWrapper.prototype, "level", {
+        get: function () { var _a; return (_a = this.logger.level) !== null && _a !== void 0 ? _a : LogLevel.Warn; },
+        enumerable: false,
+        configurable: true
+    });
+    LoggerWrapper.prototype.log = function (message) {
+        this.info(message);
+    };
+    LoggerWrapper.prototype.debug = function (message) {
+        if (this.isLogLevelEnabled(LogLevel.Debug)) {
+            this.logger.debug(message);
+        }
+    };
+    LoggerWrapper.prototype.info = function (message) {
+        if (this.isLogLevelEnabled(LogLevel.Info)) {
+            this.logger.info(message);
+        }
+    };
+    LoggerWrapper.prototype.warn = function (message) {
+        if (this.isLogLevelEnabled(LogLevel.Warn)) {
+            this.logger.warn(message);
+        }
+    };
+    LoggerWrapper.prototype.error = function (message, err) {
+        var _a;
+        if (this.isLogLevelEnabled(LogLevel.Error)) {
+            var logMessage = err
+                ? message + '\n' + (0, Utils_1.errorToString)(err, true)
+                : message;
+            this.logger.error(logMessage);
+        }
+        (_a = this.hooks) === null || _a === void 0 ? void 0 : _a.emit("clientError", message, err);
+    };
+    LoggerWrapper.prototype.isLogLevelEnabled = function (logLevel) {
+        return this.level >= logLevel;
+    };
+    return LoggerWrapper;
+}());
+exports.LoggerWrapper = LoggerWrapper;
 var ConfigCatConsoleLogger = /** @class */ (function () {
@@ -9,40 +61,29 @@ /**
      */
-    function ConfigCatConsoleLogger(logLevel) {
+    function ConfigCatConsoleLogger(level) {
+        if (level === void 0) { level = LogLevel.Warn; }
+        this.level = level;
         this.SOURCE = "ConfigCat";
-        this.level = index_1.LogLevel.Warn;
-        if (logLevel) {
-            this.level = logLevel;
-        }
     }
-    /**
-     * @deprecated Use `debug(message: string)` method instead of this
-     */
+    /** @inheritdoc */
     ConfigCatConsoleLogger.prototype.log = function (message) {
         this.info(message);
     };
+    /** @inheritdoc */
     ConfigCatConsoleLogger.prototype.debug = function (message) {
-        if (this.isLogLevelEnabled(index_1.LogLevel.Debug)) {
-            console.info(this.SOURCE + " - DEBUG - " + message);
-        }
+        console.info(this.SOURCE + " - DEBUG - " + message);
     };
+    /** @inheritdoc */
     ConfigCatConsoleLogger.prototype.info = function (message) {
-        if (this.isLogLevelEnabled(index_1.LogLevel.Info)) {
-            console.info(this.SOURCE + " - INFO - " + message);
-        }
+        console.info(this.SOURCE + " - INFO - " + message);
     };
+    /** @inheritdoc */
     ConfigCatConsoleLogger.prototype.warn = function (message) {
-        if (this.isLogLevelEnabled(index_1.LogLevel.Warn)) {
-            console.warn(this.SOURCE + " - WARN - " + message);
-        }
+        console.warn(this.SOURCE + " - WARN - " + message);
     };
+    /** @inheritdoc */
     ConfigCatConsoleLogger.prototype.error = function (message) {
-        if (this.isLogLevelEnabled(index_1.LogLevel.Error)) {
-            console.error(this.SOURCE + " - ERROR - " + message);
-        }
+        console.error(this.SOURCE + " - ERROR - " + message);
     };
-    ConfigCatConsoleLogger.prototype.isLogLevelEnabled = function (logLevel) {
-        return this.level >= logLevel;
-    };
     return ConfigCatConsoleLogger;
 }());
 exports.ConfigCatConsoleLogger = ConfigCatConsoleLogger;

lib/ConfigServiceBase.d.ts

@@ -1,17 +0,53 @@
-import { IConfigFetcher } from "./index";
 import { OptionsBase } from "./ConfigCatClientOptions";
+import { FetchResult, IConfigFetcher } from "./ConfigFetcher";
 import { ProjectConfig } from "./ProjectConfig";
+export declare class RefreshResult {
+    errorMessage: string | null;
+    errorException?: any;
+    constructor(errorMessage: string | null, errorException?: any);
+    get isSuccess(): boolean;
+    static from(fetchResult: FetchResult): RefreshResult;
+    static success(): RefreshResult;
+    static failure(errorMessage: string, errorException?: any): RefreshResult;
+}
 export interface IConfigService {
     getConfig(): Promise<ProjectConfig | null>;
-    refreshConfigAsync(): Promise<ProjectConfig | null>;
+    refreshConfigAsync(): Promise<[RefreshResult, ProjectConfig | null]>;
+    get isOffline(): boolean;
+    setOnline(): void;
+    setOffline(): void;
+    dispose(): void;
 }
-export declare abstract class ConfigServiceBase {
+declare enum ConfigServiceStatus {
+    Online = 0,
+    Offline = 1,
+    Disposed = 2
+}
+export declare abstract class ConfigServiceBase<TOptions extends OptionsBase> {
     protected configFetcher: IConfigFetcher;
-    protected baseConfig: OptionsBase;
-    private fetchLogicCallbacks;
-    constructor(configFetcher: IConfigFetcher, baseConfig: OptionsBase);
-    protected refreshLogicBaseAsync(lastProjectConfig: ProjectConfig | null, forceUpdateCache?: boolean): Promise<ProjectConfig | null>;
-    private fetchLogic;
-    private fetchLogicInternal;
+    protected options: TOptions;
+    private status;
+    private pendingFetch;
+    constructor(configFetcher: IConfigFetcher, options: TOptions);
+    dispose(): void;
+    protected get disposed(): boolean;
+    abstract getConfig(): Promise<ProjectConfig | null>;
+    refreshConfigAsync(): Promise<[RefreshResult, ProjectConfig | null]>;
+    protected refreshConfigCoreAsync(latestConfig: ProjectConfig | null): Promise<[FetchResult, ProjectConfig | null]>;
+    protected onConfigUpdated(newConfig: ProjectConfig): void;
+    protected onConfigChanged(newConfig: ProjectConfig): void;
+    private fetchAsync;
+    private fetchLogicAsync;
+    private fetchRequestAsync;
+    protected get isOfflineExactly(): boolean;
+    get isOffline(): boolean;
+    protected setOnlineCore(): void;
+    setOnline(): void;
+    protected setOfflineCore(): void;
+    setOffline(): void;
+    logStatusChange(status: ConfigServiceStatus): void;
+    logOfflineModeWarning(): void;
+    logDisposedWarning(methodName: string): void;
 }
+export {};
 //# sourceMappingURL=ConfigServiceBase.d.ts.map

lib/ConfigServiceBase.js

 "use strict";
-var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
-    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
-    return new (P || (P = Promise))(function (resolve, reject) {
-        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
-        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
-        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
-        step((generator = generator.apply(thisArg, _arguments || [])).next());
-    });
-};
-var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
-    function verb(n) { return function (v) { return step([n, v]); }; }
-    function step(op) {
-        if (f) throw new TypeError("Generator is already executing.");
-        while (_) try {
-            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
-            if (y = 0, t) op = [op[0] & 2, t.value];
-            switch (op[0]) {
-                case 0: case 1: t = op; break;
-                case 4: _.label++; return { value: op[1], done: false };
-                case 5: _.label++; y = op[1]; op = [0]; continue;
-                case 7: op = _.ops.pop(); _.trys.pop(); continue;
-                default:
-                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
-                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
-                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
-                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
-                    if (t[2]) _.ops.pop();
-                    _.trys.pop(); continue;
-            }
-            op = body.call(thisArg, _);
-        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
-        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
-    }
-};
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.ConfigServiceBase = void 0;
-var index_1 = require("./index");
+exports.ConfigServiceBase = exports.RefreshResult = void 0;
+var tslib_1 = require("tslib");
+var ConfigFetcher_1 = require("./ConfigFetcher");
 var ProjectConfig_1 = require("./ProjectConfig");
+var RefreshResult = /** @class */ (function () {
+    function RefreshResult(errorMessage, errorException) {
+        this.errorMessage = errorMessage;
+        this.errorException = errorException;
+    }
+    Object.defineProperty(RefreshResult.prototype, "isSuccess", {
+        get: function () { return this.errorMessage === null; },
+        enumerable: false,
+        configurable: true
+    });
+    RefreshResult.from = function (fetchResult) {
+        return fetchResult.status !== ConfigFetcher_1.FetchStatus.Errored
+            ? RefreshResult.success()
+            : RefreshResult.failure(fetchResult.errorMessage, fetchResult.errorException);
+    };
+    RefreshResult.success = function () {
+        return new RefreshResult(null);
+    };
+    RefreshResult.failure = function (errorMessage, errorException) {
+        return new RefreshResult(errorMessage, errorException);
+    };
+    return RefreshResult;
+}());
+exports.RefreshResult = RefreshResult;
+var ConfigServiceStatus;
+(function (ConfigServiceStatus) {
+    ConfigServiceStatus[ConfigServiceStatus["Online"] = 0] = "Online";
+    ConfigServiceStatus[ConfigServiceStatus["Offline"] = 1] = "Offline";
+    ConfigServiceStatus[ConfigServiceStatus["Disposed"] = 2] = "Disposed";
+})(ConfigServiceStatus || (ConfigServiceStatus = {}));
 var ConfigServiceBase = /** @class */ (function () {
-    function ConfigServiceBase(configFetcher, baseConfig) {
-        this.fetchLogicCallbacks = [];
+    function ConfigServiceBase(configFetcher, options) {
+        this.pendingFetch = null;
         this.configFetcher = configFetcher;
-        this.baseConfig = baseConfig;
+        this.options = options;
+        this.status = options.offline ? ConfigServiceStatus.Offline : ConfigServiceStatus.Online;
     }
-    ConfigServiceBase.prototype.refreshLogicBaseAsync = function (lastProjectConfig, forceUpdateCache) {
-        var _this = this;
-        if (forceUpdateCache === void 0) { forceUpdateCache = true; }
-        this.baseConfig.logger.debug("ConfigServiceBase.refreshLogicBaseAsync() - called.");
-        return new Promise(function (resolve) {
-            var _a;
-            _this.fetchLogic(_this.baseConfig, (_a = lastProjectConfig === null || lastProjectConfig === void 0 ? void 0 : lastProjectConfig.HttpETag) !== null && _a !== void 0 ? _a : null, 0, function (newConfig) { return __awaiter(_this, void 0, void 0, function () {
-                return __generator(this, function (_a) {
-                    switch (_a.label) {
-                        case 0:
-                            if (!(newConfig && newConfig.ConfigJSON)) return [3 /*break*/, 2];
-                            this.baseConfig.logger.debug("ConfigServiceBase.refreshLogicBaseAsync() - fetchLogic() success, returning config.");
-                            return [4 /*yield*/, this.baseConfig.cache.set(this.baseConfig.getCacheKey(), newConfig)];
-                        case 1:
-                            _a.sent();
-                            resolve(newConfig);
-                            return [3 /*break*/, 5];
-                        case 2:
-                            if (!(forceUpdateCache && lastProjectConfig && lastProjectConfig.ConfigJSON)) return [3 /*break*/, 4];
-                            this.baseConfig.logger.debug("ConfigServiceBase.refreshLogicBaseAsync() - fetchLogic() didn't return a config, setting the cache with last config with new timestamp, returning last config.");
-                            lastProjectConfig.Timestamp = new Date().getTime();
-                            return [4 /*yield*/, this.baseConfig.cache.set(this.baseConfig.getCacheKey(), lastProjectConfig)];
-                        case 3:
-                            _a.sent();
-                            resolve(lastProjectConfig);
-                            return [3 /*break*/, 5];
-                        case 4:
-                            this.baseConfig.logger.debug("ConfigServiceBase.refreshLogicBaseAsync() - fetchLogic() didn't return a config, returing last config.");
-                            resolve(lastProjectConfig);
-                            _a.label = 5;
-                        case 5: return [2 /*return*/];
-                    }
-                });
-            }); });
+    ConfigServiceBase.prototype.dispose = function () {
+        this.status = ConfigServiceStatus.Disposed;
+    };
+    Object.defineProperty(ConfigServiceBase.prototype, "disposed", {
+        get: function () { return this.status === ConfigServiceStatus.Disposed; },
+        enumerable: false,
+        configurable: true
+    });
+    ConfigServiceBase.prototype.refreshConfigAsync = function () {
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var latestConfig, _a, fetchResult, config;
+            return tslib_1.__generator(this, function (_b) {
+                switch (_b.label) {
+                    case 0: return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
+                    case 1:
+                        latestConfig = _b.sent();
+                        if (!!this.isOffline) return [3 /*break*/, 3];
+                        return [4 /*yield*/, this.refreshConfigCoreAsync(latestConfig)];
+                    case 2:
+                        _a = _b.sent(), fetchResult = _a[0], config = _a[1];
+                        return [2 /*return*/, [RefreshResult.from(fetchResult), config]];
+                    case 3:
+                        this.logOfflineModeWarning();
+                        return [2 /*return*/, [RefreshResult.failure("Client is in offline mode, it can't initiate HTTP calls."), latestConfig]];
+                }
+            });
         });
     };
-    ConfigServiceBase.prototype.fetchLogic = function (options, lastEtag, retries, callback) {
-        var _this = this;
-        this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic() - called.");
-        var calledBaseUrl = this.baseConfig.baseUrl;
-        this.fetchLogicInternal(this.baseConfig, lastEtag, retries, function (result) {
-            _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): result.status: " + (result === null || result === void 0 ? void 0 : result.status));
-            if (!result || result.status != index_1.FetchStatus.Fetched || ProjectConfig_1.ProjectConfig.compareEtags(lastEtag !== null && lastEtag !== void 0 ? lastEtag : '', result.eTag)) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): result.status != FetchStatus.Fetched or etags are the same. Returning null.");
-                callback(null);
-                return;
-            }
-            if (!result.responseBody) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): no response body. Returning null.");
-                callback(null);
-                return;
-            }
-            var newConfig = new ProjectConfig_1.ProjectConfig(new Date().getTime(), result.responseBody, result.eTag);
-            var preferences = newConfig.ConfigJSON[ProjectConfig_1.ConfigFile.Preferences];
-            if (!preferences) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): preferences is empty. Returning newConfig.");
-                callback(newConfig);
-                return;
-            }
-            var baseUrl = preferences[ProjectConfig_1.Preferences.BaseUrl];
-            // If the base_url is the same as the last called one, just return the response.
-            if (!baseUrl || baseUrl == calledBaseUrl) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): baseUrl OK. Returning newConfig.");
-                callback(newConfig);
-                return;
-            }
-            var redirect = preferences[ProjectConfig_1.Preferences.Redirect];
-            // If the base_url is overridden, and the redirect parameter is not 2 (force),
-            // the SDK should not redirect the calls and it just have to return the response.
-            if (options.baseUrlOverriden && redirect !== 2) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): options.baseUrlOverriden && redirect !== 2.");
-                callback(newConfig);
-                return;
-            }
-            options.baseUrl = baseUrl;
-            if (redirect === 0) {
-                callback(newConfig);
-                return;
-            }
-            if (redirect === 1) {
-                options.logger.warn("Your dataGovernance parameter at ConfigCatClient initialization is not in sync " +
-                    "with your preferences on the ConfigCat Dashboard: " +
-                    "https://app.configcat.com/organization/data-governance. " +
-                    "Only Organization Admins can access this preference.");
-            }
-            if (retries >= 2) {
-                options.logger.error("Redirect loop during config.json fetch. Please contact [e-mail].");
-                callback(newConfig);
-                return;
-            }
-            _this.fetchLogic(options, lastEtag, ++retries, callback);
-            return;
+    ConfigServiceBase.prototype.refreshConfigCoreAsync = function (latestConfig) {
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var _a, fetchResult, newConfig, configContentHasChanged;
+            return tslib_1.__generator(this, function (_b) {
+                switch (_b.label) {
+                    case 0: return [4 /*yield*/, this.fetchAsync(latestConfig)];
+                    case 1:
+                        _a = _b.sent(), fetchResult = _a[0], newConfig = _a[1];
+                        configContentHasChanged = !ProjectConfig_1.ProjectConfig.equals(latestConfig, newConfig);
+                        if (!(newConfig && (configContentHasChanged || newConfig.Timestamp > latestConfig.Timestamp))) return [3 /*break*/, 3];
+                        return [4 /*yield*/, this.options.cache.set(this.options.getCacheKey(), newConfig)];
+                    case 2:
+                        _b.sent();
+                        this.onConfigUpdated(newConfig);
+                        if (configContentHasChanged) {
+                            this.onConfigChanged(newConfig);
+                        }
+                        return [2 /*return*/, [fetchResult, newConfig]];
+                    case 3: return [2 /*return*/, [fetchResult, latestConfig]];
+                }
+            });
         });
     };
-    ConfigServiceBase.prototype.fetchLogicInternal = function (options, lastEtag, retries, callback) {
+    ConfigServiceBase.prototype.onConfigUpdated = function (newConfig) { };
+    ConfigServiceBase.prototype.onConfigChanged = function (newConfig) {
+        this.options.logger.debug("config changed");
+        this.options.hooks.emit("configChanged", newConfig);
+    };
+    ConfigServiceBase.prototype.fetchAsync = function (lastConfig) {
         var _this = this;
-        this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): called.");
-        if (retries === 0) { // Only lock on the top-level calls, not on the recursive calls (config.json redirections).
-            this.fetchLogicCallbacks.push(callback);
-            if (this.fetchLogicCallbacks.length > 1) {
-                // The first fetchLogic call is already in progress.
-                this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): The first fetchLogic call is already in progress. this.fetchLogicCallbacks.length = " + this.fetchLogicCallbacks.length);
-                return;
-            }
-            this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): Calling fetchLogic");
-            this.configFetcher.fetchLogic(options, lastEtag, function (newProjectConfig) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): fetchLogic() success, calling callbacks. this.fetchLogicCallbacks.length = " + _this.fetchLogicCallbacks.length);
-                while (_this.fetchLogicCallbacks.length) {
-                    var thisCallback = _this.fetchLogicCallbacks.pop();
-                    if (thisCallback) {
-                        _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): fetchLogic() success, calling callback.");
-                        thisCallback(newProjectConfig);
-                    }
+        var _a;
+        return (_a = this.pendingFetch) !== null && _a !== void 0 ? _a : (this.pendingFetch = (function () { return tslib_1.__awaiter(_this, void 0, void 0, function () {
+            return tslib_1.__generator(this, function (_a) {
+                switch (_a.label) {
+                    case 0:
+                        _a.trys.push([0, , 2, 3]);
+                        return [4 /*yield*/, this.fetchLogicAsync(lastConfig)];
+                    case 1: return [2 /*return*/, _a.sent()];
+                    case 2:
+                        this.pendingFetch = null;
+                        return [7 /*endfinally*/];
+                    case 3: return [2 /*return*/];
                 }
             });
+        }); })());
+    };
+    ConfigServiceBase.prototype.fetchLogicAsync = function (lastConfig) {
+        var _a;
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var options, errorMessage, _b, response, configJson, err_1, errorMessage_1;
+            return tslib_1.__generator(this, function (_c) {
+                switch (_c.label) {
+                    case 0:
+                        options = this.options;
+                        options.logger.debug("ConfigServiceBase.fetchLogicAsync() - called.");
+                        _c.label = 1;
+                    case 1:
+                        _c.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.fetchRequestAsync((_a = lastConfig === null || lastConfig === void 0 ? void 0 : lastConfig.HttpETag) !== null && _a !== void 0 ? _a : null)];
+                    case 2:
+                        _b = _c.sent(), response = _b[0], configJson = _b[1];
+                        switch (response.statusCode) {
+                            case 200: // OK
+                                if (!configJson) {
+                                    errorMessage = "Fetch was successful but HTTP response was invalid";
+                                    options.logger.debug("ConfigServiceBase.fetchLogicAsync(): ".concat(errorMessage.charAt(0).toLowerCase()).concat(errorMessage.slice(1), ". Returning null."));
+                                    return [2 /*return*/, [ConfigFetcher_1.FetchResult.error(errorMessage), null]];
+                                }
+                                options.logger.debug("ConfigServiceBase.fetchLogicAsync(): fetch was successful. Returning new config.");
+                                return [2 /*return*/, [ConfigFetcher_1.FetchResult.success(response.body, response.eTag), new ProjectConfig_1.ProjectConfig(new Date().getTime(), configJson, response.eTag)]];
+                            case 304: // Not Modified
+                                if (!lastConfig) {
+                                    errorMessage = "HTTP response ".concat(response.statusCode, " ").concat(response.reasonPhrase, " was received when no config is cached locally");
+                                    options.logger.debug("ConfigServiceBase.fetchLogicAsync(): ".concat(errorMessage.charAt(0).toLowerCase()).concat(errorMessage.slice(1), ". Returning null."));
+                                    return [2 /*return*/, [ConfigFetcher_1.FetchResult.error(errorMessage), null]];
+                                }
+                                options.logger.debug("ConfigServiceBase.fetchLogicAsync(): content was not modified. Returning last config with updated timestamp.");
+                                return [2 /*return*/, [ConfigFetcher_1.FetchResult.notModified(), new ProjectConfig_1.ProjectConfig(new Date().getTime(), lastConfig.ConfigJSON, lastConfig.HttpETag)]];
+                            case 403: // Forbidden
+                            case 404: // Not Found
+                                errorMessage = "Double-check your SDK Key at https://app.configcat.com/sdkkey";
+                                options.logger.error(errorMessage);
+                                options.logger.debug("ConfigServiceBase.fetchLogicAsync(): fetch was unsuccessful. Returning last config (if any) with updated timestamp.");
+                                return [2 /*return*/, [ConfigFetcher_1.FetchResult.error(errorMessage), lastConfig ? new ProjectConfig_1.ProjectConfig(new Date().getTime(), lastConfig.ConfigJSON, lastConfig.HttpETag) : null]];
+                            default:
+                                errorMessage = "Unexpected HTTP response was received: ".concat(response.statusCode, " ").concat(response.reasonPhrase);
+                                options.logger.error(errorMessage);
+                                options.logger.debug("ConfigServiceBase.fetchLogicAsync(): fetch was unsuccessful. Returning null.");
+                                return [2 /*return*/, [ConfigFetcher_1.FetchResult.error(errorMessage), null]];
+                        }
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_1 = _c.sent();
+                        errorMessage_1 = err_1 instanceof ConfigFetcher_1.FetchError
+                            ? err_1.message
+                            : "Unexpected error occurred during fetching.";
+                        options.logger.error(errorMessage_1, err_1);
+                        options.logger.debug("ConfigServiceBase.fetchLogicAsync(): fetch was unsuccessful. Returning null.");
+                        return [2 /*return*/, [ConfigFetcher_1.FetchResult.error(errorMessage_1, err_1), null]];
+                    case 4: return [2 /*return*/];
+                }
+            });
+        });
+    };
+    ConfigServiceBase.prototype.fetchRequestAsync = function (lastETag, maxRetryCount) {
+        if (maxRetryCount === void 0) { maxRetryCount = 2; }
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var options, retryNumber, response, configJSON, preferences, baseUrl, redirect;
+            return tslib_1.__generator(this, function (_a) {
+                switch (_a.label) {
+                    case 0:
+                        options = this.options;
+                        options.logger.debug("ConfigServiceBase.fetchRequestAsync() - called.");
+                        retryNumber = 0;
+                        _a.label = 1;
+                    case 1:
+                        options.logger.debug("ConfigServiceBase.fetchRequestAsync(): calling fetchLogic()".concat(retryNumber > 0 ? ", retry ".concat(retryNumber, "/").concat(maxRetryCount) : ""));
+                        return [4 /*yield*/, this.configFetcher.fetchLogic(options, lastETag)];
+                    case 2:
+                        response = _a.sent();
+                        if (response.statusCode !== 200) {
+                            return [2 /*return*/, [response]];
+                        }
+                        if (!response.body) {
+                            options.logger.debug("ConfigServiceBase.fetchRequestAsync(): no response body.");
+                            return [2 /*return*/, [response]];
+                        }
+                        configJSON = void 0;
+                        try {
+                            configJSON = JSON.parse(response.body);
+                        }
+                        catch (_b) {
+                            options.logger.debug("ConfigServiceBase.fetchRequestAsync(): invalid response body.");
+                            return [2 /*return*/, [response]];
+                        }
+                        preferences = configJSON[ProjectConfig_1.ConfigFile.Preferences];
+                        if (!preferences) {
+                            options.logger.debug("ConfigServiceBase.fetchRequestAsync(): preferences is empty.");
+                            return [2 /*return*/, [response, configJSON]];
+                        }
+                        baseUrl = preferences[ProjectConfig_1.Preferences.BaseUrl];
+                        // If the base_url is the same as the last called one, just return the response.
+                        if (!baseUrl || baseUrl == options.baseUrl) {
+                            options.logger.debug("ConfigServiceBase.fetchRequestAsync(): baseUrl OK.");
+                            return [2 /*return*/, [response, configJSON]];
+                        }
+                        redirect = preferences[ProjectConfig_1.Preferences.Redirect];
+                        // If the base_url is overridden, and the redirect parameter is not 2 (force),
+                        // the SDK should not redirect the calls and it just have to return the response.
+                        if (options.baseUrlOverriden && redirect !== 2) {
+                            options.logger.debug("ConfigServiceBase.fetchRequestAsync(): options.baseUrlOverriden && redirect !== 2.");
+                            return [2 /*return*/, [response, configJSON]];
+                        }
+                        options.baseUrl = baseUrl;
+                        if (redirect === 0) {
+                            return [2 /*return*/, [response, configJSON]];
+                        }
+                        if (redirect === 1) {
+                            options.logger.warn("Your dataGovernance parameter at ConfigCatClient initialization is not in sync " +
+                                "with your preferences on the ConfigCat Dashboard: " +
+                                "https://app.configcat.com/organization/data-governance. " +
+                                "Only Organization Admins can access this preference.");
+                        }
+                        if (retryNumber >= maxRetryCount) {
+                            options.logger.error("Redirect loop during config.json fetch. Please contact [e-mail].");
+                            return [2 /*return*/, [response, configJSON]];
+                        }
+                        _a.label = 3;
+                    case 3:
+                        retryNumber++;
+                        return [3 /*break*/, 1];
+                    case 4: return [2 /*return*/];
+                }
+            });
+        });
+    };
+    Object.defineProperty(ConfigServiceBase.prototype, "isOfflineExactly", {
+        get: function () {
+            return this.status === ConfigServiceStatus.Offline;
+        },
+        enumerable: false,
+        configurable: true
+    });
+    Object.defineProperty(ConfigServiceBase.prototype, "isOffline", {
+        get: function () {
+            return this.status !== ConfigServiceStatus.Online;
+        },
+        enumerable: false,
+        configurable: true
+    });
+    ConfigServiceBase.prototype.setOnlineCore = function () { };
+    ConfigServiceBase.prototype.setOnline = function () {
+        if (this.status === ConfigServiceStatus.Offline) {
+            this.setOnlineCore();
+            this.status = ConfigServiceStatus.Online;
+            this.logStatusChange(this.status);
         }
-        else {
-            // Recursive calls should call the fetchLogic as is.
-            this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): calling fetchLogic(), recursive call. retries = " + retries);
-            this.configFetcher.fetchLogic(options, lastEtag, callback);
+        else if (this.disposed) {
+            this.logDisposedWarning("setOnline");
         }
     };
+    ConfigServiceBase.prototype.setOfflineCore = function () { };
+    ConfigServiceBase.prototype.setOffline = function () {
+        if (this.status == ConfigServiceStatus.Online) {
+            this.setOfflineCore();
+            this.status = ConfigServiceStatus.Offline;
+            this.logStatusChange(this.status);
+        }
+        else if (this.disposed) {
+            this.logDisposedWarning("setOnline");
+        }
+    };
+    ConfigServiceBase.prototype.logStatusChange = function (status) {
+        var _a;
+        this.options.logger.debug("Switched to ".concat((_a = ConfigServiceStatus[status]) === null || _a === void 0 ? void 0 : _a.toUpperCase(), " mode."));
+    };
+    ConfigServiceBase.prototype.logOfflineModeWarning = function () {
+        this.options.logger.warn("Client is in offline mode, it can't initiate HTTP calls.");
+    };
+    ConfigServiceBase.prototype.logDisposedWarning = function (methodName) {
+        this.options.logger.warn("Client has already been disposed, thus ".concat(methodName, "() has no effect."));
+    };
     return ConfigServiceBase;
 }());
 exports.ConfigServiceBase = ConfigServiceBase;

lib/esm/AutoPollConfigService.js

@@ -1,84 +0,92 @@
-var __extends = (this && this.__extends) || (function () {
-    var extendStatics = function (d, b) {
-        extendStatics = Object.setPrototypeOf ||
-            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
-            function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
-        return extendStatics(d, b);
-    };
-    return function (d, b) {
-        if (typeof b !== "function" && b !== null)
-            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
-        extendStatics(d, b);
-        function __() { this.constructor = d; }
-        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
-    };
-})();
-var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
-    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
-    return new (P || (P = Promise))(function (resolve, reject) {
-        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
-        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
-        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
-        step((generator = generator.apply(thisArg, _arguments || [])).next());
-    });
-};
-var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
-    function verb(n) { return function (v) { return step([n, v]); }; }
-    function step(op) {
-        if (f) throw new TypeError("Generator is already executing.");
-        while (_) try {
-            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
-            if (y = 0, t) op = [op[0] & 2, t.value];
-            switch (op[0]) {
-                case 0: case 1: t = op; break;
-                case 4: _.label++; return { value: op[1], done: false };
-                case 5: _.label++; y = op[1]; op = [0]; continue;
-                case 7: op = _.ops.pop(); _.trys.pop(); continue;
-                default:
-                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
-                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
-                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
-                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
-                    if (t[2]) _.ops.pop();
-                    _.trys.pop(); continue;
-            }
-            op = body.call(thisArg, _);
-        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
-        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
-    }
-};
+import { __awaiter, __extends, __generator } from "tslib";
 import { ConfigServiceBase } from "./ConfigServiceBase";
 import { ProjectConfig } from "./ProjectConfig";
+import { delay } from "./Utils";
 var AutoPollConfigService = /** @class */ (function (_super) {
     __extends(AutoPollConfigService, _super);
-    function AutoPollConfigService(configFetcher, autoPollConfig) {
-        var _this = _super.call(this, configFetcher, autoPollConfig) || this;
-        _this.disposed = false;
-        _this.configChanged = autoPollConfig.configChanged;
-        _this.autoPollConfig = autoPollConfig;
-        _this.startRefreshWorker(autoPollConfig.pollIntervalSeconds * 1000);
-        _this.maxInitWaitTimeStamp = new Date().getTime() + (autoPollConfig.maxInitWaitTimeSeconds * 1000);
+    function AutoPollConfigService(configFetcher, options) {
+        var _this = _super.call(this, configFetcher, options) || this;
+        _this.signalInitialization = (void 0); // the initial value is only for keeping the TS compiler happy
+        if (options.maxInitWaitTimeSeconds > 0) {
+            _this.initialized = false;
+            // This promise will be resolved when
+            // 1. the cache contains a valid config at startup (see startRefreshWorker) or
+            // 2. config.json is downloaded the first time (see onConfigUpdated) or
+            // 3. maxInitWaitTimeSeconds has passed (see the setTimeout call below).
+            _this.initialization = new Promise(function (resolve) { return _this.signalInitialization = function () {
+                _this.initialized = true;
+                resolve();
+            }; });
+            _this.initialization.then(function () { return !_this.disposed && options.hooks.emit("clientReady"); });
+            setTimeout(function () { return _this.signalInitialization(); }, options.maxInitWaitTimeSeconds * 1000);
+        }
+        else {
+            _this.initialized = true;
+            _this.initialization = Promise.resolve();
+            options.hooks.emit("clientReady");
+        }
+        if (!options.offline) {
+            _this.startRefreshWorker(options.pollIntervalSeconds * 1000);
+        }
         return _this;
     }
+    AutoPollConfigService.prototype.waitForInitializationAsync = function () {
+        return __awaiter(this, void 0, void 0, function () {
+            var cancelDelay, result;
+            var _this = this;
+            return __generator(this, function (_a) {
+                switch (_a.label) {
+                    case 0: return [4 /*yield*/, Promise.race([
+                            (function () { return __awaiter(_this, void 0, void 0, function () { return __generator(this, function (_a) {
+                                switch (_a.label) {
+                                    case 0: return [4 /*yield*/, this.initialization];
+                                    case 1:
+                                        _a.sent();
+                                        return [2 /*return*/, true];
+                                }
+                            }); }); })(),
+                            delay(this.options.maxInitWaitTimeSeconds * 1000, function (cancel) { return cancelDelay = cancel; })
+                        ])];
+                    case 1:
+                        result = _a.sent();
+                        cancelDelay();
+                        return [2 /*return*/, !!result];
+                }
+            });
+        });
+    };
     AutoPollConfigService.prototype.getConfig = function () {
         return __awaiter(this, void 0, void 0, function () {
-            var p;
+            function logSuccess(logger) {
+                logger.debug("AutoPollConfigService.getConfig() - returning value from cache.");
+            }
+            var cacheConfig;
             return __generator(this, function (_a) {
                 switch (_a.label) {
                     case 0:
-                        this.autoPollConfig.logger.debug("AutoPollConfigService.getConfig() called.");
-                        return [4 /*yield*/, this.tryReadFromCache(0)];
+                        this.options.logger.debug("AutoPollConfigService.getConfig() called.");
+                        cacheConfig = null;
+                        if (!(!this.isOffline && !this.initialized)) return [3 /*break*/, 3];
+                        return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
                     case 1:
-                        p = _a.sent();
-                        if (!p) {
-                            this.autoPollConfig.logger.debug("AutoPollConfigService.getConfig() - cache is empty, refreshing the cache.");
-                            return [2 /*return*/, this.refreshLogic(true)];
+                        cacheConfig = _a.sent();
+                        if (!ProjectConfig.isExpired(cacheConfig, this.options.pollIntervalSeconds * 1000)) {
+                            logSuccess(this.options.logger);
+                            return [2 /*return*/, cacheConfig];
                         }
+                        this.options.logger.debug("AutoPollConfigService.getConfig() - cache is empty or expired, waiting for initialization.");
+                        return [4 /*yield*/, this.waitForInitializationAsync()];
+                    case 2:
+                        _a.sent();
+                        _a.label = 3;
+                    case 3: return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
+                    case 4:
+                        cacheConfig = _a.sent();
+                        if (!ProjectConfig.isExpired(cacheConfig, this.options.pollIntervalSeconds * 1000)) {
+                            logSuccess(this.options.logger);
+                        }
                         else {
-                            this.autoPollConfig.logger.debug("AutoPollConfigService.getConfig() - returning value from cache.");
-                            return [2 /*return*/, new Promise(function (resolve) { return resolve(p); })];
+                            this.options.logger.debug("AutoPollConfigService.getConfig() - cache is empty or expired.");
                         }
-                        return [2 /*return*/];
+                        return [2 /*return*/, cacheConfig];
                 }
@@ -89,92 +97,83 @@ });
     AutoPollConfigService.prototype.refreshConfigAsync = function () {
-        this.autoPollConfig.logger.debug("AutoPollConfigService.refreshConfigAsync() called.");
-        return this.refreshLogic(true);
+        this.options.logger.debug("AutoPollConfigService.refreshConfigAsync() called.");
+        return _super.prototype.refreshConfigAsync.call(this);
     };
     AutoPollConfigService.prototype.dispose = function () {
-        this.autoPollConfig.logger.debug("AutoPollConfigService.dispose() called.");
-        this.disposed = true;
+        this.options.logger.debug("AutoPollConfigService.dispose() called.");
+        _super.prototype.dispose.call(this);
         if (this.timerId) {
-            this.autoPollConfig.logger.debug("AutoPollConfigService.dispose() - clearing setTimeout.");
-            clearTimeout(this.timerId);
+            this.stopRefreshWorker();
         }
     };
-    AutoPollConfigService.prototype.refreshLogic = function (forceUpdateCache) {
-        var _this = this;
-        this.autoPollConfig.logger.debug("AutoPollConfigService.refreshLogic() - called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var cachedConfig, newConfig, weDontHaveCachedYetButHaveNew, weHaveBothButTheyDiffers;
+    AutoPollConfigService.prototype.onConfigUpdated = function (newConfig) {
+        _super.prototype.onConfigUpdated.call(this, newConfig);
+        this.signalInitialization();
+    };
+    AutoPollConfigService.prototype.onConfigChanged = function (newConfig) {
+        _super.prototype.onConfigChanged.call(this, newConfig);
+        this.options.configChanged();
+    };
+    AutoPollConfigService.prototype.setOnlineCore = function () {
+        this.startRefreshWorker(this.options.pollIntervalSeconds * 1000);
+    };
+    AutoPollConfigService.prototype.setOfflineCore = function () {
+        this.stopRefreshWorker();
+    };
+    AutoPollConfigService.prototype.startRefreshWorker = function (delayMs) {
+        return __awaiter(this, void 0, void 0, function () {
+            var latestConfig;
+            var _this = this;
             return __generator(this, function (_a) {
                 switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.baseConfig.cache.get(this.baseConfig.getCacheKey())];
+                    case 0:
+                        this.options.logger.debug("AutoPollConfigService.startRefreshWorker() called.");
+                        return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
                     case 1:
-                        cachedConfig = _a.sent();
-                        return [4 /*yield*/, this.refreshLogicBaseAsync(cachedConfig, forceUpdateCache)];
+                        latestConfig = _a.sent();
+                        if (!ProjectConfig.isExpired(latestConfig, this.options.pollIntervalSeconds * 1000)) return [3 /*break*/, 4];
+                        if (!!this.isOfflineExactly) return [3 /*break*/, 3];
+                        return [4 /*yield*/, this.refreshConfigCoreAsync(latestConfig)];
                     case 2:
-                        newConfig = _a.sent();
-                        weDontHaveCachedYetButHaveNew = !cachedConfig && newConfig;
-                        weHaveBothButTheyDiffers = cachedConfig && newConfig && !ProjectConfig.equals(cachedConfig, newConfig);
-                        this.autoPollConfig.logger.debug("AutoPollConfigService.refreshLogic() - weDontHaveCachedYetButHaveNew: ." + weDontHaveCachedYetButHaveNew + ". weHaveBothButTheyDiffers: " + weHaveBothButTheyDiffers + ".");
-                        if (weDontHaveCachedYetButHaveNew || weHaveBothButTheyDiffers) {
-                            this.configChanged();
-                        }
-                        resolve(newConfig);
+                        _a.sent();
+                        _a.label = 3;
+                    case 3: return [3 /*break*/, 5];
+                    case 4:
+                        this.signalInitialization();
+                        _a.label = 5;
+                    case 5:
+                        this.options.logger.debug("AutoPollConfigService.startRefreshWorker() - calling refreshWorkerLogic()'s setTimeout.");
+                        this.timerId = setTimeout(function (d) { return _this.refreshWorkerLogic(d); }, delayMs, delayMs);
                         return [2 /*return*/];
                 }
             });
-        }); });
-    };
-    AutoPollConfigService.prototype.startRefreshWorker = function (delay) {
-        var _this = this;
-        this.autoPollConfig.logger.debug("AutoPollConfigService.startRefreshWorker() called.");
-        this.refreshLogic(true).then(function (_) {
-            _this.autoPollConfig.logger.debug("AutoPollConfigService.startRefreshWorker() - calling refreshWorkerLogic()'s setTimeout.");
-            setTimeout(function () { return _this.refreshWorkerLogic(delay); }, delay);
         });
     };
-    AutoPollConfigService.prototype.refreshWorkerLogic = function (delay) {
-        var _this = this;
-        if (this.disposed) {
-            this.autoPollConfig.logger.debug("AutoPollConfigService.refreshWorkerLogic() - called on a disposed client.");
-            return;
-        }
-        this.autoPollConfig.logger.debug("AutoPollConfigService.refreshWorkerLogic() - called.");
-        this.refreshLogic(false).then(function (_) {
-            _this.autoPollConfig.logger.debug("AutoPollConfigService.refreshWorkerLogic() - calling refreshWorkerLogic()'s setTimeout.");
-            _this.timerId = setTimeout(function () {
-                _this.refreshWorkerLogic(delay);
-            }, delay);
-        });
+    AutoPollConfigService.prototype.stopRefreshWorker = function () {
+        this.options.logger.debug("AutoPollConfigService.stopRefreshWorker() - clearing setTimeout.");
+        clearTimeout(this.timerId);
     };
-    AutoPollConfigService.prototype.tryReadFromCache = function (tries) {
+    AutoPollConfigService.prototype.refreshWorkerLogic = function (delayMs) {
         return __awaiter(this, void 0, void 0, function () {
-            var p, diff, delay;
+            var latestConfig;
+            var _this = this;
             return __generator(this, function (_a) {
                 switch (_a.label) {
                     case 0:
-                        this.autoPollConfig.logger.debug("AutoPollConfigService.tryReadFromCache() - called. Tries: " + tries + ".");
-                        return [4 /*yield*/, this.baseConfig.cache.get(this.baseConfig.getCacheKey())];
+                        if (this.disposed) {
+                            this.options.logger.debug("AutoPollConfigService.refreshWorkerLogic() - called on a disposed client.");
+                            return [2 /*return*/];
+                        }
+                        this.options.logger.debug("AutoPollConfigService.refreshWorkerLogic() - called.");
+                        if (!!this.isOffline) return [3 /*break*/, 3];
+                        return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
                     case 1:
-                        p = _a.sent();
-                        if (!(this.maxInitWaitTimeStamp > new Date().getTime()
-                            && (
-                            // Wait for maxInitWaitTimeStamp in case the cache is empty
-                            !p
-                                // Wait for maxInitWaitTimeStamp in case of an expired cache (if its timestamp is older than the pollIntervalSeconds)
-                                || p.Timestamp < new Date().getTime() - this.autoPollConfig.pollIntervalSeconds * 1000))) return [3 /*break*/, 3];
-                        if (!p) {
-                            this.autoPollConfig.logger.debug("AutoPollConfigService.tryReadFromCache() - waiting for maxInitWaitTimeStamp because cache is empty.");
-                        }
-                        else {
-                            this.autoPollConfig.logger.debug("AutoPollConfigService.tryReadFromCache() - waiting for maxInitWaitTimeStamp because cache is expired.");
-                        }
-                        diff = this.maxInitWaitTimeStamp - new Date().getTime();
-                        delay = 30 + (tries * tries * 20);
-                        return [4 /*yield*/, this.sleep(Math.min(diff, delay))];
+                        latestConfig = _a.sent();
+                        return [4 /*yield*/, this.refreshConfigCoreAsync(latestConfig)];
                     case 2:
                         _a.sent();
-                        tries++;
-                        return [2 /*return*/, this.tryReadFromCache(tries)];
+                        _a.label = 3;
                     case 3:
-                        this.autoPollConfig.logger.debug("AutoPollConfigService.tryReadFromCache() - returning value from cache.");
-                        return [2 /*return*/, new Promise(function (resolve) { return resolve(p); })];
+                        this.options.logger.debug("AutoPollConfigService.refreshWorkerLogic() - calling refreshWorkerLogic()'s setTimeout.");
+                        this.timerId = setTimeout(function (d) { return _this.refreshWorkerLogic(d); }, delayMs, delayMs);
+                        return [2 /*return*/];
                 }
@@ -184,7 +183,4 @@ });
     };
-    AutoPollConfigService.prototype.sleep = function (ms) {
-        return new Promise(function (resolve) { return setTimeout(resolve, ms); });
-    };
     return AutoPollConfigService;
 }(ConfigServiceBase));
 export { AutoPollConfigService };

lib/esm/Cache.js

@@ -9,3 +9,4 @@ var InMemoryCache = /** @class */ (function () {
     InMemoryCache.prototype.get = function (key) {
-        return this.cache[key];
+        var _a;
+        return (_a = this.cache[key]) !== null && _a !== void 0 ? _a : null;
     };
@@ -12,0 +13,0 @@ return InMemoryCache;

lib/esm/ConfigCatClient.js

@@ -1,59 +0,66 @@
-var __assign = (this && this.__assign) || function () {
-    __assign = Object.assign || function(t) {
-        for (var s, i = 1, n = arguments.length; i < n; i++) {
-            s = arguments[i];
-            for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
-                t[p] = s[p];
+import { __assign, __awaiter, __generator } from "tslib";
+import { AutoPollConfigService } from "./AutoPollConfigService";
+import { AutoPollOptions, LazyLoadOptions, ManualPollOptions, PollingMode } from "./ConfigCatClientOptions";
+import { RefreshResult } from "./ConfigServiceBase";
+import { OverrideBehaviour } from "./FlagOverrides";
+import { LazyLoadConfigService } from "./LazyLoadConfigService";
+import { ManualPollConfigService } from "./ManualPollConfigService";
+import { ConfigFile } from "./ProjectConfig";
+import { checkSettingsAvailable, ensureAllowedDefaultValue, evaluate, evaluateAll, evaluateAllVariationIds, evaluateVariationId, evaluationDetailsFromDefaultValue, evaluationDetailsFromDefaultVariationId, RolloutEvaluator } from "./RolloutEvaluator";
+import { errorToString, getSettingsFromConfig, getTimestampAsDate } from "./Utils";
+var ConfigCatClientCache = /** @class */ (function () {
+    function ConfigCatClientCache() {
+        this.instances = {};
+    }
+    ConfigCatClientCache.prototype.getOrCreate = function (options, configCatKernel) {
+        var instance;
+        var cachedInstance = this.instances[options.apiKey];
+        if (cachedInstance) {
+            var weakRef = cachedInstance[0];
+            instance = weakRef.deref();
+            if (instance) {
+                return [instance, true];
+            }
         }
-        return t;
+        var token = {};
+        instance = new ConfigCatClient(options, configCatKernel, token);
+        this.instances[options.apiKey] = [new WeakRef(instance), token];
+        return [instance, false];
     };
-    return __assign.apply(this, arguments);
-};
-var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
-    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
-    return new (P || (P = Promise))(function (resolve, reject) {
-        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
-        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
-        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
-        step((generator = generator.apply(thisArg, _arguments || [])).next());
-    });
-};
-var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
-    function verb(n) { return function (v) { return step([n, v]); }; }
-    function step(op) {
-        if (f) throw new TypeError("Generator is already executing.");
-        while (_) try {
-            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
-            if (y = 0, t) op = [op[0] & 2, t.value];
-            switch (op[0]) {
-                case 0: case 1: t = op; break;
-                case 4: _.label++; return { value: op[1], done: false };
-                case 5: _.label++; y = op[1]; op = [0]; continue;
-                case 7: op = _.ops.pop(); _.trys.pop(); continue;
-                default:
-                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
-                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
-                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
-                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
-                    if (t[2]) _.ops.pop();
-                    _.trys.pop(); continue;
+    ConfigCatClientCache.prototype.remove = function (sdkKey, cacheToken) {
+        var cachedInstance = this.instances[sdkKey];
+        if (cachedInstance) {
+            var weakRef = cachedInstance[0], token = cachedInstance[1];
+            var instanceIsAvailable = !!weakRef.deref();
+            if (!instanceIsAvailable || token === cacheToken) {
+                delete this.instances[sdkKey];
+                return instanceIsAvailable;
             }
-            op = body.call(thisArg, _);
-        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
-        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
-    }
-};
-import { AutoPollOptions, ManualPollOptions, LazyLoadOptions } from "./ConfigCatClientOptions";
-import { AutoPollConfigService } from "./AutoPollConfigService";
-import { LazyLoadConfigService } from "./LazyLoadConfigService";
-import { ManualPollService } from "./ManualPollService";
-import { RolloutEvaluator } from "./RolloutEvaluator";
-import { ConfigFile } from "./ProjectConfig";
-import { OverrideBehaviour } from "./FlagOverrides";
-import { getSettingsFromConfig } from "./Utils";
+        }
+        return false;
+    };
+    ConfigCatClientCache.prototype.clear = function () {
+        var removedInstances = [];
+        for (var _i = 0, _a = Object.entries(this.instances); _i < _a.length; _i++) {
+            var _b = _a[_i], sdkKey = _b[0], weakRef = _b[1][0];
+            var instance = weakRef.deref();
+            if (instance) {
+                removedInstances.push(instance);
+            }
+            delete this.instances[sdkKey];
+        }
+        return removedInstances;
+    };
+    return ConfigCatClientCache;
+}());
+export { ConfigCatClientCache };
+var clientInstanceCache = new ConfigCatClientCache();
 var ConfigCatClient = /** @class */ (function () {
-    function ConfigCatClient(options, configCatKernel) {
+    function ConfigCatClient(options, configCatKernel, cacheToken) {
         var _a;
+        this.cacheToken = cacheToken;
+        /** @inheritdoc */
+        this.addListener = this.on;
+        /** @inheritdoc */
+        this.off = this.removeListener;
         if (!options) {
@@ -70,189 +77,317 @@ throw new Error("Invalid 'options' value");
         }
-        if (options === null || options === void 0 ? void 0 : options.defaultUser) {
+        if (options.defaultUser) {
             this.setDefaultUser(options.defaultUser);
         }
         this.evaluator = new RolloutEvaluator(options.logger);
-        if (((_a = options === null || options === void 0 ? void 0 : options.flagOverrides) === null || _a === void 0 ? void 0 : _a.behaviour) != OverrideBehaviour.LocalOnly) {
-            if (options && options instanceof LazyLoadOptions) {
-                this.configService = new LazyLoadConfigService(configCatKernel.configFetcher, options);
-            }
-            else if (options && options instanceof ManualPollOptions) {
-                this.configService = new ManualPollService(configCatKernel.configFetcher, options);
-            }
-            else if (options && options instanceof AutoPollOptions) {
-                this.configService = new AutoPollConfigService(configCatKernel.configFetcher, options);
-            }
-            else {
-                throw new Error("Invalid 'options' value");
-            }
+        if (((_a = options.flagOverrides) === null || _a === void 0 ? void 0 : _a.behaviour) != OverrideBehaviour.LocalOnly) {
+            var configServiceClass = options instanceof AutoPollOptions ? AutoPollConfigService :
+                options instanceof ManualPollOptions ? ManualPollConfigService :
+                    options instanceof LazyLoadOptions ? LazyLoadConfigService :
+                        (function () { throw new Error("Invalid 'options' value"); })();
+            this.configService = new configServiceClass(configCatKernel.configFetcher, options);
         }
+        else {
+            this.options.hooks.emit("clientReady");
+        }
+        this.suppressFinalize = registerForFinalization(this, { sdkKey: options.apiKey, cacheToken: cacheToken, configService: this.configService, logger: options.logger });
     }
+    Object.defineProperty(ConfigCatClient, "instanceCache", {
+        get: function () { return clientInstanceCache; },
+        enumerable: false,
+        configurable: true
+    });
+    ;
+    ConfigCatClient.get = function (sdkKey, pollingMode, options, configCatKernel) {
+        if (!sdkKey) {
+            throw new Error("Invalid 'sdkKey' value");
+        }
+        var optionsClass = pollingMode === PollingMode.AutoPoll ? AutoPollOptions :
+            pollingMode === PollingMode.ManualPoll ? ManualPollOptions :
+                pollingMode === PollingMode.LazyLoad ? LazyLoadOptions :
+                    (function () { throw new Error("Invalid 'pollingMode' value"); })();
+        var actualOptions = new optionsClass(sdkKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache, configCatKernel.eventEmitterFactory);
+        var _a = clientInstanceCache.getOrCreate(actualOptions, configCatKernel), instance = _a[0], instanceAlreadyCreated = _a[1];
+        if (instanceAlreadyCreated && options) {
+            actualOptions.logger.warn("Client for SDK key '".concat(sdkKey, "' is already created and will be reused; configuration action is being ignored."));
+        }
+        return instance;
+    };
+    ConfigCatClient.finalize = function (data) {
+        // Safeguard against situations where user forgets to dispose of the client instance.
+        var _a;
+        (_a = data.logger) === null || _a === void 0 ? void 0 : _a.debug("finalize() called");
+        if (data.cacheToken) {
+            clientInstanceCache.remove(data.sdkKey, data.cacheToken);
+        }
+        ConfigCatClient.close(data.configService, data.logger);
+    };
+    ConfigCatClient.close = function (configService, logger, hooks) {
+        logger === null || logger === void 0 ? void 0 : logger.debug("close() called");
+        hooks === null || hooks === void 0 ? void 0 : hooks.tryDisconnect();
+        configService === null || configService === void 0 ? void 0 : configService.dispose();
+    };
     ConfigCatClient.prototype.dispose = function () {
-        this.options.logger.debug("dispose() called");
-        if (this.configService instanceof AutoPollConfigService) {
-            this.options.logger.debug("Disposing AutoPollConfigService");
-            this.configService.dispose();
+        var options = this.options;
+        options.logger.debug("dispose() called");
+        if (this.cacheToken) {
+            clientInstanceCache.remove(options.apiKey, this.cacheToken);
         }
+        ConfigCatClient.close(this.configService, options.logger, options.hooks);
+        this.suppressFinalize();
     };
+    ConfigCatClient.disposeAll = function () {
+        var removedInstances = clientInstanceCache.clear();
+        var errors;
+        for (var _i = 0, removedInstances_1 = removedInstances; _i < removedInstances_1.length; _i++) {
+            var instance = removedInstances_1[_i];
+            try {
+                ConfigCatClient.close(instance.configService, instance.options.logger, instance.options.hooks);
+                instance.suppressFinalize();
+            }
+            catch (err) {
+                errors !== null && errors !== void 0 ? errors : (errors = []);
+                errors.push(err);
+            }
+        }
+        if (errors) {
+            throw typeof AggregateError !== "undefined" ? new AggregateError(errors) : errors.pop();
+        }
+    };
     ConfigCatClient.prototype.getValue = function (key, defaultValue, callback, user) {
         this.options.logger.debug("getValue() called.");
-        this.getValueAsync(key, defaultValue, user).then(function (value) {
-            callback(value);
-        });
+        this.getValueAsync(key, defaultValue, user).then(callback);
     };
     ConfigCatClient.prototype.getValueAsync = function (key, defaultValue, user) {
-        var _this = this;
-        this.options.logger.debug("getValueAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var settings, result;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getSettingsAsync()];
+        return __awaiter(this, void 0, void 0, function () {
+            var value, evaluationDetails, remoteConfig, settings, err_1;
+            var _a;
+            return __generator(this, function (_b) {
+                switch (_b.label) {
+                    case 0:
+                        this.options.logger.debug("getValueAsync() called.");
+                        remoteConfig = null;
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _b.label = 1;
                     case 1:
-                        settings = _a.sent();
-                        if (!settings) {
-                            this.options.logger.error("config.json is not present. Returning default value: '" + defaultValue + "'.");
-                            resolve(defaultValue);
-                            return [2 /*return*/];
-                        }
-                        result = this.evaluator.Evaluate(settings, key, defaultValue, user !== null && user !== void 0 ? user : this.defaultUser).Value;
-                        resolve(result);
-                        return [2 /*return*/];
+                        _b.trys.push([1, 3, , 4]);
+                        ensureAllowedDefaultValue(defaultValue);
+                        settings = void 0;
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _b.sent(), settings = _a[0], remoteConfig = _a[1];
+                        evaluationDetails = evaluate(this.evaluator, settings, key, defaultValue, user, remoteConfig, this.options.logger);
+                        value = evaluationDetails.value;
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_1 = _b.sent();
+                        this.options.logger.error("Error occurred in getValueAsync().", err_1);
+                        evaluationDetails = evaluationDetailsFromDefaultValue(key, defaultValue, getTimestampAsDate(remoteConfig), user, errorToString(err_1), err_1);
+                        value = defaultValue;
+                        return [3 /*break*/, 4];
+                    case 4:
+                        this.options.hooks.emit("flagEvaluated", evaluationDetails);
+                        return [2 /*return*/, value];
                 }
             });
-        }); });
-    };
-    ConfigCatClient.prototype.forceRefresh = function (callback) {
-        this.options.logger.debug("forceRefresh() called.");
-        this.forceRefreshAsync().then(function () {
-            callback();
         });
     };
-    ConfigCatClient.prototype.forceRefreshAsync = function () {
-        var _this = this;
-        this.options.logger.debug("forceRefreshAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
+    ConfigCatClient.prototype.getValueDetails = function (key, defaultValue, callback, user) {
+        this.options.logger.debug("getValueDetails() called.");
+        this.getValueDetailsAsync(key, defaultValue, user).then(callback);
+    };
+    ConfigCatClient.prototype.getValueDetailsAsync = function (key, defaultValue, user) {
+        return __awaiter(this, void 0, void 0, function () {
+            var evaluationDetails, remoteConfig, settings, err_2;
             var _a;
             return __generator(this, function (_b) {
                 switch (_b.label) {
-                    case 0: return [4 /*yield*/, ((_a = this.configService) === null || _a === void 0 ? void 0 : _a.refreshConfigAsync())];
+                    case 0:
+                        this.options.logger.debug("getValueDetailsAsync() called.");
+                        remoteConfig = null;
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _b.label = 1;
                     case 1:
-                        _b.sent();
-                        resolve();
-                        return [2 /*return*/];
+                        _b.trys.push([1, 3, , 4]);
+                        ensureAllowedDefaultValue(defaultValue);
+                        settings = void 0;
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _b.sent(), settings = _a[0], remoteConfig = _a[1];
+                        evaluationDetails = evaluate(this.evaluator, settings, key, defaultValue, user, remoteConfig, this.options.logger);
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_2 = _b.sent();
+                        this.options.logger.error("Error occurred in getValueDetailsAsync().", err_2);
+                        evaluationDetails = evaluationDetailsFromDefaultValue(key, defaultValue, getTimestampAsDate(remoteConfig), user, errorToString(err_2), err_2);
+                        return [3 /*break*/, 4];
+                    case 4:
+                        this.options.hooks.emit("flagEvaluated", evaluationDetails);
+                        return [2 /*return*/, evaluationDetails];
                 }
             });
-        }); });
+        });
     };
+    ConfigCatClient.prototype.forceRefresh = function (callback) {
+        this.options.logger.debug("forceRefresh() called.");
+        this.forceRefreshAsync().then(callback);
+    };
+    ConfigCatClient.prototype.forceRefreshAsync = function () {
+        return __awaiter(this, void 0, void 0, function () {
+            var result, err_3;
+            return __generator(this, function (_a) {
+                switch (_a.label) {
+                    case 0:
+                        this.options.logger.debug("forceRefreshAsync() called.");
+                        if (!this.configService) return [3 /*break*/, 5];
+                        _a.label = 1;
+                    case 1:
+                        _a.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.configService.refreshConfigAsync()];
+                    case 2:
+                        result = (_a.sent())[0];
+                        return [2 /*return*/, result];
+                    case 3:
+                        err_3 = _a.sent();
+                        this.options.logger.error("Error occurred in forceRefreshAsync().", err_3);
+                        return [2 /*return*/, RefreshResult.failure(errorToString(err_3), err_3)];
+                    case 4: return [3 /*break*/, 6];
+                    case 5: return [2 /*return*/, RefreshResult.failure("Client is configured to use the LocalOnly override behavior, which prevents making HTTP requests.")];
+                    case 6: return [2 /*return*/];
+                }
+            });
+        });
+    };
     ConfigCatClient.prototype.getAllKeys = function (callback) {
         this.options.logger.debug("getAllKeys() called.");
-        this.getAllKeysAsync().then(function (value) {
-            callback(value);
-        });
+        this.getAllKeysAsync().then(callback);
     };
     ConfigCatClient.prototype.getAllKeysAsync = function () {
-        var _this = this;
-        this.options.logger.debug("getAllKeysAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var settings;
+        return __awaiter(this, void 0, void 0, function () {
+            var settings, err_4;
             return __generator(this, function (_a) {
                 switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getSettingsAsync()];
+                    case 0:
+                        this.options.logger.debug("getAllKeysAsync() called.");
+                        _a.label = 1;
                     case 1:
-                        settings = _a.sent();
-                        if (!settings) {
-                            this.options.logger.error("config.json is not present, returning empty array");
-                            resolve([]);
-                            return [2 /*return*/];
+                        _a.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        settings = (_a.sent())[0];
+                        if (!checkSettingsAvailable(settings, this.options.logger, ", returning empty array")) {
+                            return [2 /*return*/, []];
                         }
-                        resolve(Object.keys(settings));
-                        return [2 /*return*/];
+                        return [2 /*return*/, Object.keys(settings)];
+                    case 3:
+                        err_4 = _a.sent();
+                        this.options.logger.error("Error occurred in getAllKeysAsync().", err_4);
+                        return [2 /*return*/, []];
+                    case 4: return [2 /*return*/];
                 }
             });
-        }); });
+        });
     };
     ConfigCatClient.prototype.getVariationId = function (key, defaultVariationId, callback, user) {
         this.options.logger.debug("getVariationId() called.");
-        this.getVariationIdAsync(key, defaultVariationId, user).then(function (variationId) {
-            callback(variationId);
-        });
+        this.getVariationIdAsync(key, defaultVariationId, user).then(callback);
     };
     ConfigCatClient.prototype.getVariationIdAsync = function (key, defaultVariationId, user) {
-        var _this = this;
-        this.options.logger.debug("getVariationIdAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var settings, result;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getSettingsAsync()];
+        return __awaiter(this, void 0, void 0, function () {
+            var variationId, evaluationDetails, remoteConfig, settings, err_5;
+            var _a;
+            return __generator(this, function (_b) {
+                switch (_b.label) {
+                    case 0:
+                        this.options.logger.debug("getVariationIdAsync() called.");
+                        remoteConfig = null;
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _b.label = 1;
                     case 1:
-                        settings = _a.sent();
-                        if (!settings) {
-                            this.options.logger.error("config.json is not present. Returning default variationId: '" + defaultVariationId + "'.");
-                            resolve(defaultVariationId);
-                            return [2 /*return*/];
-                        }
-                        result = this.evaluator.Evaluate(settings, key, null, user !== null && user !== void 0 ? user : this.defaultUser, defaultVariationId).VariationId;
-                        resolve(result);
-                        return [2 /*return*/];
+                        _b.trys.push([1, 3, , 4]);
+                        settings = void 0;
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _b.sent(), settings = _a[0], remoteConfig = _a[1];
+                        evaluationDetails = evaluateVariationId(this.evaluator, settings, key, defaultVariationId, user, remoteConfig, this.options.logger);
+                        variationId = evaluationDetails.variationId;
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_5 = _b.sent();
+                        this.options.logger.error("Error occurred in getVariationIdAsync().", err_5);
+                        evaluationDetails = evaluationDetailsFromDefaultVariationId(key, defaultVariationId, getTimestampAsDate(remoteConfig), user, errorToString(err_5), err_5);
+                        variationId = defaultVariationId;
+                        return [3 /*break*/, 4];
+                    case 4:
+                        this.options.hooks.emit("flagEvaluated", evaluationDetails);
+                        return [2 /*return*/, variationId];
                 }
             });
-        }); });
+        });
     };
     ConfigCatClient.prototype.getAllVariationIds = function (callback, user) {
         this.options.logger.debug("getAllVariationIds() called.");
-        this.getAllVariationIdsAsync(user).then(function (variationIds) {
-            callback(variationIds);
-        });
+        this.getAllVariationIdsAsync(user).then(callback);
     };
     ConfigCatClient.prototype.getAllVariationIdsAsync = function (user) {
-        var _this = this;
-        this.options.logger.debug("getAllVariationIdsAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var keys, promises, variationIds;
-            var _this = this;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getAllKeysAsync()];
+        return __awaiter(this, void 0, void 0, function () {
+            var result, evaluationDetailsArray, _a, settings, remoteConfig, errors, err_6, _i, evaluationDetailsArray_1, evaluationDetail;
+            var _b;
+            return __generator(this, function (_c) {
+                switch (_c.label) {
+                    case 0:
+                        this.options.logger.debug("getAllVariationIdsAsync() called.");
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _c.label = 1;
                     case 1:
-                        keys = _a.sent();
-                        if (keys.length === 0) {
-                            resolve([]);
-                            return [2 /*return*/];
+                        _c.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _c.sent(), settings = _a[0], remoteConfig = _a[1];
+                        errors = void 0;
+                        _b = evaluateAllVariationIds(this.evaluator, settings, user, remoteConfig, this.options.logger), evaluationDetailsArray = _b[0], errors = _b[1];
+                        if (errors === null || errors === void 0 ? void 0 : errors.length) {
+                            throw typeof AggregateError !== "undefined" ? new AggregateError(errors) : errors.pop();
                         }
-                        promises = keys.map(function (key) { return _this.getVariationIdAsync(key, null, user); });
-                        return [4 /*yield*/, Promise.all(promises)];
-                    case 2:
-                        variationIds = _a.sent();
-                        resolve(variationIds);
-                        return [2 /*return*/];
+                        result = evaluationDetailsArray.filter(function (details) { return details !== null && details !== void 0; }).map(function (details) { return details.variationId; });
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_6 = _c.sent();
+                        this.options.logger.error("Error occurred in getAllVariationIdsAsync().", err_6);
+                        evaluationDetailsArray !== null && evaluationDetailsArray !== void 0 ? evaluationDetailsArray : (evaluationDetailsArray = []);
+                        result = [];
+                        return [3 /*break*/, 4];
+                    case 4:
+                        for (_i = 0, evaluationDetailsArray_1 = evaluationDetailsArray; _i < evaluationDetailsArray_1.length; _i++) {
+                            evaluationDetail = evaluationDetailsArray_1[_i];
+                            this.options.hooks.emit("flagEvaluated", evaluationDetail);
+                        }
+                        return [2 /*return*/, result];
                 }
             });
-        }); });
+        });
     };
     ConfigCatClient.prototype.getKeyAndValue = function (variationId, callback) {
         this.options.logger.debug("getKeyAndValue() called.");
-        this.getKeyAndValueAsync(variationId).then(function (settingKeyAndValue) {
-            callback(settingKeyAndValue);
-        });
+        this.getKeyAndValueAsync(variationId).then(callback);
     };
     ConfigCatClient.prototype.getKeyAndValueAsync = function (variationId) {
-        var _this = this;
-        this.options.logger.debug("getKeyAndValueAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var settings, settingKey, rolloutRules, i, rolloutRule, percentageItems, i, percentageItem;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getSettingsAsync()];
+        return __awaiter(this, void 0, void 0, function () {
+            var settings, _i, _a, _b, settingKey, setting, rolloutRules, i, rolloutRule, percentageItems, i, percentageItem, err_7;
+            return __generator(this, function (_c) {
+                switch (_c.label) {
+                    case 0:
+                        this.options.logger.debug("getKeyAndValueAsync() called.");
+                        _c.label = 1;
                     case 1:
-                        settings = _a.sent();
-                        if (!settings) {
-                            this.options.logger.error("config.json is not present, returning empty array");
-                            resolve(null);
-                            return [2 /*return*/];
+                        _c.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        settings = (_c.sent())[0];
+                        if (!checkSettingsAvailable(settings, this.options.logger, ", returning null")) {
+                            return [2 /*return*/, null];
                         }
-                        for (settingKey in settings) {
-                            if (variationId === settings[settingKey].variationId) {
-                                resolve({ settingKey: settingKey, settingValue: settings[settingKey].value });
-                                return [2 /*return*/];
+                        for (_i = 0, _a = Object.entries(settings); _i < _a.length; _i++) {
+                            _b = _a[_i], settingKey = _b[0], setting = _b[1];
+                            if (variationId === setting.variationId) {
+                                return [2 /*return*/, new SettingKeyValue(settingKey, setting.value)];
                             }
@@ -264,4 +399,3 @@ rolloutRules = settings[settingKey].rolloutRules;
                                     if (variationId === rolloutRule.variationId) {
-                                        resolve({ settingKey: settingKey, settingValue: rolloutRule.value });
-                                        return [2 /*return*/];
+                                        return [2 /*return*/, new SettingKeyValue(settingKey, rolloutRule.value)];
                                     }
@@ -275,4 +409,3 @@ }
                                     if (variationId === percentageItem.variationId) {
-                                        resolve({ settingKey: settingKey, settingValue: percentageItem.value });
-                                        return [2 /*return*/];
+                                        return [2 /*return*/, new SettingKeyValue(settingKey, percentageItem.value)];
                                     }
@@ -283,44 +416,94 @@ }
                         this.options.logger.error("Could not find the setting for the given variation ID: " + variationId);
-                        resolve(null);
-                        return [2 /*return*/];
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_7 = _c.sent();
+                        this.options.logger.error("Error occurred in getKeyAndValueAsync().", err_7);
+                        return [3 /*break*/, 4];
+                    case 4: return [2 /*return*/, null];
                 }
             });
-        }); });
+        });
     };
     ConfigCatClient.prototype.getAllValues = function (callback, user) {
         this.options.logger.debug("getAllValues() called.");
-        this.getAllValuesAsync(user).then(function (value) {
-            callback(value);
-        });
+        this.getAllValuesAsync(user).then(callback);
     };
     ConfigCatClient.prototype.getAllValuesAsync = function (user) {
-        var _this = this;
-        this.options.logger.debug("getAllValuesAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var settings, keys, result;
-            var _this = this;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0: return [4 /*yield*/, this.getSettingsAsync()];
+        return __awaiter(this, void 0, void 0, function () {
+            var result, evaluationDetailsArray, _a, settings, remoteConfig, errors, err_8, _i, evaluationDetailsArray_2, evaluationDetail;
+            var _b;
+            return __generator(this, function (_c) {
+                switch (_c.label) {
+                    case 0:
+                        this.options.logger.debug("getAllValuesAsync() called.");
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _c.label = 1;
                     case 1:
-                        settings = _a.sent();
-                        if (!settings) {
-                            this.options.logger.error("config.json is not present, returning empty array");
-                            resolve([]);
-                            return [2 /*return*/];
+                        _c.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _c.sent(), settings = _a[0], remoteConfig = _a[1];
+                        errors = void 0;
+                        _b = evaluateAll(this.evaluator, settings, user, remoteConfig, this.options.logger), evaluationDetailsArray = _b[0], errors = _b[1];
+                        if (errors === null || errors === void 0 ? void 0 : errors.length) {
+                            throw typeof AggregateError !== "undefined" ? new AggregateError(errors) : errors.pop();
                         }
-                        keys = Object.keys(settings);
+                        result = evaluationDetailsArray.map(function (details) { return new SettingKeyValue(details.key, details.value); });
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_8 = _c.sent();
+                        this.options.logger.error("Error occurred in getAllValuesAsync().", err_8);
+                        evaluationDetailsArray !== null && evaluationDetailsArray !== void 0 ? evaluationDetailsArray : (evaluationDetailsArray = []);
                         result = [];
-                        keys.forEach(function (key) {
-                            result.push({
-                                settingKey: key,
-                                settingValue: _this.evaluator.Evaluate(settings, key, undefined, user !== null && user !== void 0 ? user : _this.defaultUser).Value
-                            });
-                        });
-                        resolve(result);
-                        return [2 /*return*/];
+                        return [3 /*break*/, 4];
+                    case 4:
+                        for (_i = 0, evaluationDetailsArray_2 = evaluationDetailsArray; _i < evaluationDetailsArray_2.length; _i++) {
+                            evaluationDetail = evaluationDetailsArray_2[_i];
+                            this.options.hooks.emit("flagEvaluated", evaluationDetail);
+                        }
+                        return [2 /*return*/, result];
                 }
             });
-        }); });
+        });
     };
+    ConfigCatClient.prototype.getAllValueDetails = function (callback, user) {
+        this.options.logger.debug("getAllValueDetails() called.");
+        this.getAllValueDetailsAsync(user).then(callback);
+    };
+    ConfigCatClient.prototype.getAllValueDetailsAsync = function (user) {
+        return __awaiter(this, void 0, void 0, function () {
+            var evaluationDetailsArray, _a, settings, remoteConfig, errors, err_9, _i, evaluationDetailsArray_3, evaluationDetail;
+            var _b;
+            return __generator(this, function (_c) {
+                switch (_c.label) {
+                    case 0:
+                        this.options.logger.debug("getAllValueDetailsAsync() called.");
+                        user !== null && user !== void 0 ? user : (user = this.defaultUser);
+                        _c.label = 1;
+                    case 1:
+                        _c.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.getSettingsAsync()];
+                    case 2:
+                        _a = _c.sent(), settings = _a[0], remoteConfig = _a[1];
+                        errors = void 0;
+                        _b = evaluateAll(this.evaluator, settings, user, remoteConfig, this.options.logger), evaluationDetailsArray = _b[0], errors = _b[1];
+                        if (errors === null || errors === void 0 ? void 0 : errors.length) {
+                            throw typeof AggregateError !== "undefined" ? new AggregateError(errors) : errors.pop();
+                        }
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_9 = _c.sent();
+                        this.options.logger.error("Error occurred in getAllValueDetailsAsync().", err_9);
+                        evaluationDetailsArray !== null && evaluationDetailsArray !== void 0 ? evaluationDetailsArray : (evaluationDetailsArray = []);
+                        return [3 /*break*/, 4];
+                    case 4:
+                        for (_i = 0, evaluationDetailsArray_3 = evaluationDetailsArray; _i < evaluationDetailsArray_3.length; _i++) {
+                            evaluationDetail = evaluationDetailsArray_3[_i];
+                            this.options.hooks.emit("flagEvaluated", evaluationDetail);
+                        }
+                        return [2 /*return*/, evaluationDetailsArray];
+                }
+            });
+        });
+    };
     ConfigCatClient.prototype.setDefaultUser = function (defaultUser) {
@@ -330,47 +513,109 @@ this.defaultUser = defaultUser;
     ConfigCatClient.prototype.clearDefaultUser = function () {
-        this.defaultUser = undefined;
+        this.defaultUser = void 0;
     };
+    Object.defineProperty(ConfigCatClient.prototype, "isOffline", {
+        get: function () {
+            var _a, _b;
+            return (_b = (_a = this.configService) === null || _a === void 0 ? void 0 : _a.isOffline) !== null && _b !== void 0 ? _b : true;
+        },
+        enumerable: false,
+        configurable: true
+    });
+    ConfigCatClient.prototype.setOnline = function () {
+        if (this.configService) {
+            this.configService.setOnline();
+        }
+        else {
+            this.options.logger.warn("Client is configured to use the LocalOnly override behavior, thus SetOnline() has no effect.");
+        }
+    };
+    ConfigCatClient.prototype.setOffline = function () {
+        var _a;
+        (_a = this.configService) === null || _a === void 0 ? void 0 : _a.setOffline();
+    };
     ConfigCatClient.prototype.getSettingsAsync = function () {
-        var _this = this;
-        this.options.logger.debug("getSettingsAsync() called.");
-        return new Promise(function (resolve) { return __awaiter(_this, void 0, void 0, function () {
-            var localSettings, remoteConfig, remoteSettings, config;
-            var _a, _b, _c;
-            return __generator(this, function (_d) {
-                switch (_d.label) {
+        var _a;
+        return __awaiter(this, void 0, void 0, function () {
+            var getRemoteConfigAsync, flagOverrides, remoteSettings, remoteConfig, localSettings, _b;
+            var _c, _d;
+            var _this = this;
+            return __generator(this, function (_e) {
+                switch (_e.label) {
                     case 0:
-                        if (!((_a = this.options) === null || _a === void 0 ? void 0 : _a.flagOverrides)) return [3 /*break*/, 3];
-                        return [4 /*yield*/, this.options.flagOverrides.dataSource.getOverrides()];
+                        this.options.logger.debug("getSettingsAsync() called.");
+                        getRemoteConfigAsync = function () { return __awaiter(_this, void 0, void 0, function () {
+                            var config, json, settings;
+                            var _a;
+                            return __generator(this, function (_b) {
+                                switch (_b.label) {
+                                    case 0: return [4 /*yield*/, ((_a = this.configService) === null || _a === void 0 ? void 0 : _a.getConfig())];
+                                    case 1:
+                                        config = _b.sent();
+                                        json = config === null || config === void 0 ? void 0 : config.ConfigJSON;
+                                        settings = (json === null || json === void 0 ? void 0 : json[ConfigFile.FeatureFlags]) ? getSettingsFromConfig(json) : null;
+                                        return [2 /*return*/, [settings, config !== null && config !== void 0 ? config : null]];
+                                }
+                            });
+                        }); };
+                        flagOverrides = (_a = this.options) === null || _a === void 0 ? void 0 : _a.flagOverrides;
+                        if (!flagOverrides) return [3 /*break*/, 7];
+                        remoteSettings = void 0;
+                        remoteConfig = void 0;
+                        return [4 /*yield*/, flagOverrides.dataSource.getOverrides()];
                     case 1:
-                        localSettings = _d.sent();
-                        if (this.options.flagOverrides.behaviour == OverrideBehaviour.LocalOnly) {
-                            resolve(localSettings);
-                            return [2 /*return*/];
+                        localSettings = _e.sent();
+                        _b = flagOverrides.behaviour;
+                        switch (_b) {
+                            case OverrideBehaviour.LocalOnly: return [3 /*break*/, 2];
+                            case OverrideBehaviour.LocalOverRemote: return [3 /*break*/, 3];
+                            case OverrideBehaviour.RemoteOverLocal: return [3 /*break*/, 5];
                         }
-                        return [4 /*yield*/, ((_b = this.configService) === null || _b === void 0 ? void 0 : _b.getConfig())];
-                    case 2:
-                        remoteConfig = _d.sent();
-                        remoteSettings = getSettingsFromConfig(remoteConfig === null || remoteConfig === void 0 ? void 0 : remoteConfig.ConfigJSON);
-                        if (this.options.flagOverrides.behaviour == OverrideBehaviour.LocalOverRemote) {
-                            resolve(__assign(__assign({}, remoteSettings), localSettings));
-                            return [2 /*return*/];
-                        }
-                        else if (this.options.flagOverrides.behaviour == OverrideBehaviour.RemoteOverLocal) {
-                            resolve(__assign(__assign({}, localSettings), remoteSettings));
-                            return [2 /*return*/];
-                        }
-                        _d.label = 3;
-                    case 3: return [4 /*yield*/, ((_c = this.configService) === null || _c === void 0 ? void 0 : _c.getConfig())];
+                        return [3 /*break*/, 7];
+                    case 2: return [2 /*return*/, [localSettings, null]];
+                    case 3: return [4 /*yield*/, getRemoteConfigAsync()];
                     case 4:
-                        config = _d.sent();
-                        if (!config || !config.ConfigJSON || !config.ConfigJSON[ConfigFile.FeatureFlags]) {
-                            resolve(null);
-                            return [2 /*return*/];
-                        }
-                        resolve(getSettingsFromConfig(config.ConfigJSON));
-                        return [2 /*return*/];
+                        _c = _e.sent(), remoteSettings = _c[0], remoteConfig = _c[1];
+                        return [2 /*return*/, [__assign(__assign({}, (remoteSettings !== null && remoteSettings !== void 0 ? remoteSettings : {})), localSettings), remoteConfig]];
+                    case 5: return [4 /*yield*/, getRemoteConfigAsync()];
+                    case 6:
+                        _d = _e.sent(), remoteSettings = _d[0], remoteConfig = _d[1];
+                        return [2 /*return*/, [__assign(__assign({}, localSettings), (remoteSettings !== null && remoteSettings !== void 0 ? remoteSettings : {})), remoteConfig]];
+                    case 7: return [4 /*yield*/, getRemoteConfigAsync()];
+                    case 8: return [2 /*return*/, _e.sent()];
                 }
             });
-        }); });
+        });
     };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.on = function (eventName, listener) {
+        this.options.hooks.on(eventName, listener);
+        return this;
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.once = function (eventName, listener) {
+        this.options.hooks.once(eventName, listener);
+        return this;
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.removeListener = function (eventName, listener) {
+        this.options.hooks.removeListener(eventName, listener);
+        return this;
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.removeAllListeners = function (eventName) {
+        this.options.hooks.removeAllListeners(eventName);
+        return this;
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.listeners = function (eventName) {
+        return this.options.hooks.listeners(eventName);
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.listenerCount = function (eventName) {
+        return this.options.hooks.listenerCount(eventName);
+    };
+    /** @inheritdoc */
+    ConfigCatClient.prototype.eventNames = function () {
+        return this.options.hooks.eventNames();
+    };
     return ConfigCatClient;
@@ -380,3 +625,5 @@ }());
 var SettingKeyValue = /** @class */ (function () {
-    function SettingKeyValue() {
+    function SettingKeyValue(settingKey, settingValue) {
+        this.settingKey = settingKey;
+        this.settingValue = settingValue;
     }
@@ -386,1 +633,22 @@ return SettingKeyValue;
 export { SettingKeyValue };
+;
+var registerForFinalization = function (client, data) {
+    // Use FinalizationRegistry (finalization callbacks) if the runtime provides that feature.
+    if (typeof FinalizationRegistry !== "undefined") {
+        var finalizationRegistry_1 = new FinalizationRegistry(function (data) { return ConfigCatClient["finalize"](data); });
+        registerForFinalization = function (client, data) {
+            var unregisterToken = {};
+            finalizationRegistry_1.register(client, data, unregisterToken);
+            return function () { return finalizationRegistry_1.unregister(unregisterToken); };
+        };
+    }
+    // If FinalizationRegistry is unavailable, we can't really track finalization.
+    // (Although we could implement something which resembles finalization callbacks using a weak map + a timer,
+    // since ConfigCatClientCache also needs to keep (weak) references to the created client instances,
+    // this hypothetical approach wouldn't work without a complete WeakRef polyfill,
+    // which is kind of impossible (for more details, see Polyfills.ts).
+    else {
+        registerForFinalization = function () { return function () { }; };
+    }
+    return registerForFinalization(client, data);
+};

lib/esm/ConfigCatClientOptions.js

@@ -1,19 +0,12 @@
-var __extends = (this && this.__extends) || (function () {
-    var extendStatics = function (d, b) {
-        extendStatics = Object.setPrototypeOf ||
-            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
-            function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
-        return extendStatics(d, b);
-    };
-    return function (d, b) {
-        if (typeof b !== "function" && b !== null)
-            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
-        extendStatics(d, b);
-        function __() { this.constructor = d; }
-        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
-    };
-})();
-import { ConfigCatConsoleLogger } from "./ConfigCatLogger";
-import { LogLevel } from "./index";
+import { __extends } from "tslib";
 import { InMemoryCache } from "./Cache";
+import { ConfigCatConsoleLogger, LoggerWrapper } from "./ConfigCatLogger";
+import { DefaultEventEmitter } from "./DefaultEventEmitter";
+import { Hooks } from "./Hooks";
+export var PollingMode;
+(function (PollingMode) {
+    PollingMode[PollingMode["AutoPoll"] = 0] = "AutoPoll";
+    PollingMode[PollingMode["LazyLoad"] = 1] = "LazyLoad";
+    PollingMode[PollingMode["ManualPoll"] = 2] = "ManualPoll";
+})(PollingMode || (PollingMode = {}));
 /** Control the location of the config.json files containing your feature flags and settings within the ConfigCat CDN. */
@@ -28,9 +21,9 @@ export var DataGovernance;
 var OptionsBase = /** @class */ (function () {
-    function OptionsBase(apiKey, clientVersion, options, defaultCache) {
-        var _a;
+    function OptionsBase(apiKey, clientVersion, options, defaultCache, eventEmitterFactory) {
+        var _a, _b, _c;
         this.configFileName = "config_v5";
-        this.logger = new ConfigCatConsoleLogger(LogLevel.Warn);
         this.requestTimeoutMs = 30000;
         this.baseUrlOverriden = false;
         this.proxy = "";
+        this.offline = false;
         if (!apiKey) {
@@ -54,6 +47,7 @@ throw new Error("Invalid 'apiKey' value");
         }
+        var eventEmitter = (_b = eventEmitterFactory === null || eventEmitterFactory === void 0 ? void 0 : eventEmitterFactory()) !== null && _b !== void 0 ? _b : new DefaultEventEmitter();
+        this.hooks = new Hooks(eventEmitter);
+        var logger;
         if (options) {
-            if (options.logger) {
-                this.logger = options.logger;
-            }
+            logger = options.logger;
             if (options.requestTimeoutMs) {
@@ -81,3 +75,8 @@ if (options.requestTimeoutMs < 0) {
             }
+            if (options.offline) {
+                this.offline = options.offline;
+            }
+            (_c = options.setupHooks) === null || _c === void 0 ? void 0 : _c.call(options, this.hooks);
         }
+        this.logger = new LoggerWrapper(logger !== null && logger !== void 0 ? logger : new ConfigCatConsoleLogger(), this.hooks);
     }
@@ -95,7 +94,9 @@ OptionsBase.prototype.getUrl = function () {
     __extends(AutoPollOptions, _super);
-    function AutoPollOptions(apiKey, sdkType, sdkVersion, options, defaultCache) {
-        var _this = _super.call(this, apiKey, sdkType + "/a-" + sdkVersion, options, defaultCache) || this;
+    function AutoPollOptions(apiKey, sdkType, sdkVersion, options, defaultCache, eventEmitterFactory) {
+        var _this = _super.call(this, apiKey, sdkType + "/a-" + sdkVersion, options, defaultCache, eventEmitterFactory) || this;
         /** The client's poll interval in seconds. Default: 60 seconds. */
         _this.pollIntervalSeconds = 60;
-        /** You can subscribe to configuration changes with this callback. */
+        /** You can subscribe to configuration changes with this callback.
+         * @deprecated This property is obsolete and will be removed from the public API in a future major version. Please use the 'options.setupHooks = hooks => hooks.on("configChanged", ...)' format instead.
+        */
         _this.configChanged = function () { };
@@ -105,3 +106,3 @@ /** Maximum waiting time between the client initialization and the first config acquisition in seconds. */
         if (options) {
-            if (options.pollIntervalSeconds !== undefined && options.pollIntervalSeconds !== null) {
+            if (options.pollIntervalSeconds !== void 0 && options.pollIntervalSeconds !== null) {
                 _this.pollIntervalSeconds = options.pollIntervalSeconds;
@@ -112,10 +113,10 @@ }
             }
-            if (options.maxInitWaitTimeSeconds !== undefined && options.maxInitWaitTimeSeconds !== null) {
+            if (options.maxInitWaitTimeSeconds !== void 0 && options.maxInitWaitTimeSeconds !== null) {
                 _this.maxInitWaitTimeSeconds = options.maxInitWaitTimeSeconds;
             }
         }
-        if (_this.pollIntervalSeconds < 1) {
+        if (!(_this.pollIntervalSeconds >= 1 && (typeof _this.pollIntervalSeconds === 'number'))) {
             throw new Error("Invalid 'pollIntervalSeconds' value");
         }
-        if (_this.maxInitWaitTimeSeconds < 0) {
+        if (!(_this.maxInitWaitTimeSeconds >= 0 && (typeof _this.maxInitWaitTimeSeconds === 'number'))) {
             throw new Error("Invalid 'maxInitWaitTimeSeconds' value");
@@ -130,4 +131,4 @@ }
     __extends(ManualPollOptions, _super);
-    function ManualPollOptions(apiKey, sdkType, sdkVersion, options, defaultCache) {
-        return _super.call(this, apiKey, sdkType + "/m-" + sdkVersion, options, defaultCache) || this;
+    function ManualPollOptions(apiKey, sdkType, sdkVersion, options, defaultCache, eventEmitterFactory) {
+        return _super.call(this, apiKey, sdkType + "/m-" + sdkVersion, options, defaultCache, eventEmitterFactory) || this;
     }
@@ -139,4 +140,4 @@ return ManualPollOptions;
     __extends(LazyLoadOptions, _super);
-    function LazyLoadOptions(apiKey, sdkType, sdkVersion, options, defaultCache) {
-        var _this = _super.call(this, apiKey, sdkType + "/l-" + sdkVersion, options, defaultCache) || this;
+    function LazyLoadOptions(apiKey, sdkType, sdkVersion, options, defaultCache, eventEmitterFactory) {
+        var _this = _super.call(this, apiKey, sdkType + "/l-" + sdkVersion, options, defaultCache, eventEmitterFactory) || this;
         /** The cache TTL. */
@@ -143,0 +144,0 @@ _this.cacheTimeToLiveSeconds = 60;

lib/esm/ConfigCatLogger.js

@@ -1,2 +0,54 @@
-import { LogLevel } from "./index";
+import { errorToString } from "./Utils";
+export var LogLevel;
+(function (LogLevel) {
+    LogLevel[LogLevel["Debug"] = 4] = "Debug";
+    LogLevel[LogLevel["Info"] = 3] = "Info";
+    LogLevel[LogLevel["Warn"] = 2] = "Warn";
+    LogLevel[LogLevel["Error"] = 1] = "Error";
+    LogLevel[LogLevel["Off"] = -1] = "Off";
+})(LogLevel || (LogLevel = {}));
+var LoggerWrapper = /** @class */ (function () {
+    function LoggerWrapper(logger, hooks) {
+        this.logger = logger;
+        this.hooks = hooks;
+    }
+    Object.defineProperty(LoggerWrapper.prototype, "level", {
+        get: function () { var _a; return (_a = this.logger.level) !== null && _a !== void 0 ? _a : LogLevel.Warn; },
+        enumerable: false,
+        configurable: true
+    });
+    LoggerWrapper.prototype.log = function (message) {
+        this.info(message);
+    };
+    LoggerWrapper.prototype.debug = function (message) {
+        if (this.isLogLevelEnabled(LogLevel.Debug)) {
+            this.logger.debug(message);
+        }
+    };
+    LoggerWrapper.prototype.info = function (message) {
+        if (this.isLogLevelEnabled(LogLevel.Info)) {
+            this.logger.info(message);
+        }
+    };
+    LoggerWrapper.prototype.warn = function (message) {
+        if (this.isLogLevelEnabled(LogLevel.Warn)) {
+            this.logger.warn(message);
+        }
+    };
+    LoggerWrapper.prototype.error = function (message, err) {
+        var _a;
+        if (this.isLogLevelEnabled(LogLevel.Error)) {
+            var logMessage = err
+                ? message + '\n' + errorToString(err, true)
+                : message;
+            this.logger.error(logMessage);
+        }
+        (_a = this.hooks) === null || _a === void 0 ? void 0 : _a.emit("clientError", message, err);
+    };
+    LoggerWrapper.prototype.isLogLevelEnabled = function (logLevel) {
+        return this.level >= logLevel;
+    };
+    return LoggerWrapper;
+}());
+export { LoggerWrapper };
 var ConfigCatConsoleLogger = /** @class */ (function () {
@@ -6,40 +58,29 @@ /**
      */
-    function ConfigCatConsoleLogger(logLevel) {
+    function ConfigCatConsoleLogger(level) {
+        if (level === void 0) { level = LogLevel.Warn; }
+        this.level = level;
         this.SOURCE = "ConfigCat";
-        this.level = LogLevel.Warn;
-        if (logLevel) {
-            this.level = logLevel;
-        }
     }
-    /**
-     * @deprecated Use `debug(message: string)` method instead of this
-     */
+    /** @inheritdoc */
     ConfigCatConsoleLogger.prototype.log = function (message) {
         this.info(message);
     };
+    /** @inheritdoc */
     ConfigCatConsoleLogger.prototype.debug = function (message) {
-        if (this.isLogLevelEnabled(LogLevel.Debug)) {
-            console.info(this.SOURCE + " - DEBUG - " + message);
-        }
+        console.info(this.SOURCE + " - DEBUG - " + message);
     };
+    /** @inheritdoc */
     ConfigCatConsoleLogger.prototype.info = function (message) {
-        if (this.isLogLevelEnabled(LogLevel.Info)) {
-            console.info(this.SOURCE + " - INFO - " + message);
-        }
+        console.info(this.SOURCE + " - INFO - " + message);
     };
+    /** @inheritdoc */
     ConfigCatConsoleLogger.prototype.warn = function (message) {
-        if (this.isLogLevelEnabled(LogLevel.Warn)) {
-            console.warn(this.SOURCE + " - WARN - " + message);
-        }
+        console.warn(this.SOURCE + " - WARN - " + message);
     };
+    /** @inheritdoc */
     ConfigCatConsoleLogger.prototype.error = function (message) {
-        if (this.isLogLevelEnabled(LogLevel.Error)) {
-            console.error(this.SOURCE + " - ERROR - " + message);
-        }
+        console.error(this.SOURCE + " - ERROR - " + message);
     };
-    ConfigCatConsoleLogger.prototype.isLogLevelEnabled = function (logLevel) {
-        return this.level >= logLevel;
-    };
     return ConfigCatConsoleLogger;
 }());
 export { ConfigCatConsoleLogger };

lib/esm/ConfigServiceBase.js

@@ -1,169 +0,293 @@
-var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
-    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
-    return new (P || (P = Promise))(function (resolve, reject) {
-        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
-        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
-        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
-        step((generator = generator.apply(thisArg, _arguments || [])).next());
+import { __awaiter, __generator } from "tslib";
+import { FetchError, FetchResult, FetchStatus } from "./ConfigFetcher";
+import { ConfigFile, Preferences, ProjectConfig } from "./ProjectConfig";
+var RefreshResult = /** @class */ (function () {
+    function RefreshResult(errorMessage, errorException) {
+        this.errorMessage = errorMessage;
+        this.errorException = errorException;
+    }
+    Object.defineProperty(RefreshResult.prototype, "isSuccess", {
+        get: function () { return this.errorMessage === null; },
+        enumerable: false,
+        configurable: true
     });
-};
-var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
-    function verb(n) { return function (v) { return step([n, v]); }; }
-    function step(op) {
-        if (f) throw new TypeError("Generator is already executing.");
-        while (_) try {
-            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
-            if (y = 0, t) op = [op[0] & 2, t.value];
-            switch (op[0]) {
-                case 0: case 1: t = op; break;
-                case 4: _.label++; return { value: op[1], done: false };
-                case 5: _.label++; y = op[1]; op = [0]; continue;
-                case 7: op = _.ops.pop(); _.trys.pop(); continue;
-                default:
-                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
-                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
-                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
-                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
-                    if (t[2]) _.ops.pop();
-                    _.trys.pop(); continue;
-            }
-            op = body.call(thisArg, _);
-        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
-        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
-    }
-};
-import { FetchStatus } from "./index";
-import { ConfigFile, Preferences, ProjectConfig } from "./ProjectConfig";
+    RefreshResult.from = function (fetchResult) {
+        return fetchResult.status !== FetchStatus.Errored
+            ? RefreshResult.success()
+            : RefreshResult.failure(fetchResult.errorMessage, fetchResult.errorException);
+    };
+    RefreshResult.success = function () {
+        return new RefreshResult(null);
+    };
+    RefreshResult.failure = function (errorMessage, errorException) {
+        return new RefreshResult(errorMessage, errorException);
+    };
+    return RefreshResult;
+}());
+export { RefreshResult };
+var ConfigServiceStatus;
+(function (ConfigServiceStatus) {
+    ConfigServiceStatus[ConfigServiceStatus["Online"] = 0] = "Online";
+    ConfigServiceStatus[ConfigServiceStatus["Offline"] = 1] = "Offline";
+    ConfigServiceStatus[ConfigServiceStatus["Disposed"] = 2] = "Disposed";
+})(ConfigServiceStatus || (ConfigServiceStatus = {}));
 var ConfigServiceBase = /** @class */ (function () {
-    function ConfigServiceBase(configFetcher, baseConfig) {
-        this.fetchLogicCallbacks = [];
+    function ConfigServiceBase(configFetcher, options) {
+        this.pendingFetch = null;
         this.configFetcher = configFetcher;
-        this.baseConfig = baseConfig;
+        this.options = options;
+        this.status = options.offline ? ConfigServiceStatus.Offline : ConfigServiceStatus.Online;
     }
-    ConfigServiceBase.prototype.refreshLogicBaseAsync = function (lastProjectConfig, forceUpdateCache) {
-        var _this = this;
-        if (forceUpdateCache === void 0) { forceUpdateCache = true; }
-        this.baseConfig.logger.debug("ConfigServiceBase.refreshLogicBaseAsync() - called.");
-        return new Promise(function (resolve) {
-            var _a;
-            _this.fetchLogic(_this.baseConfig, (_a = lastProjectConfig === null || lastProjectConfig === void 0 ? void 0 : lastProjectConfig.HttpETag) !== null && _a !== void 0 ? _a : null, 0, function (newConfig) { return __awaiter(_this, void 0, void 0, function () {
-                return __generator(this, function (_a) {
-                    switch (_a.label) {
-                        case 0:
-                            if (!(newConfig && newConfig.ConfigJSON)) return [3 /*break*/, 2];
-                            this.baseConfig.logger.debug("ConfigServiceBase.refreshLogicBaseAsync() - fetchLogic() success, returning config.");
-                            return [4 /*yield*/, this.baseConfig.cache.set(this.baseConfig.getCacheKey(), newConfig)];
-                        case 1:
-                            _a.sent();
-                            resolve(newConfig);
-                            return [3 /*break*/, 5];
-                        case 2:
-                            if (!(forceUpdateCache && lastProjectConfig && lastProjectConfig.ConfigJSON)) return [3 /*break*/, 4];
-                            this.baseConfig.logger.debug("ConfigServiceBase.refreshLogicBaseAsync() - fetchLogic() didn't return a config, setting the cache with last config with new timestamp, returning last config.");
-                            lastProjectConfig.Timestamp = new Date().getTime();
-                            return [4 /*yield*/, this.baseConfig.cache.set(this.baseConfig.getCacheKey(), lastProjectConfig)];
-                        case 3:
-                            _a.sent();
-                            resolve(lastProjectConfig);
-                            return [3 /*break*/, 5];
-                        case 4:
-                            this.baseConfig.logger.debug("ConfigServiceBase.refreshLogicBaseAsync() - fetchLogic() didn't return a config, returing last config.");
-                            resolve(lastProjectConfig);
-                            _a.label = 5;
-                        case 5: return [2 /*return*/];
-                    }
-                });
-            }); });
+    ConfigServiceBase.prototype.dispose = function () {
+        this.status = ConfigServiceStatus.Disposed;
+    };
+    Object.defineProperty(ConfigServiceBase.prototype, "disposed", {
+        get: function () { return this.status === ConfigServiceStatus.Disposed; },
+        enumerable: false,
+        configurable: true
+    });
+    ConfigServiceBase.prototype.refreshConfigAsync = function () {
+        return __awaiter(this, void 0, void 0, function () {
+            var latestConfig, _a, fetchResult, config;
+            return __generator(this, function (_b) {
+                switch (_b.label) {
+                    case 0: return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
+                    case 1:
+                        latestConfig = _b.sent();
+                        if (!!this.isOffline) return [3 /*break*/, 3];
+                        return [4 /*yield*/, this.refreshConfigCoreAsync(latestConfig)];
+                    case 2:
+                        _a = _b.sent(), fetchResult = _a[0], config = _a[1];
+                        return [2 /*return*/, [RefreshResult.from(fetchResult), config]];
+                    case 3:
+                        this.logOfflineModeWarning();
+                        return [2 /*return*/, [RefreshResult.failure("Client is in offline mode, it can't initiate HTTP calls."), latestConfig]];
+                }
+            });
         });
     };
-    ConfigServiceBase.prototype.fetchLogic = function (options, lastEtag, retries, callback) {
-        var _this = this;
-        this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic() - called.");
-        var calledBaseUrl = this.baseConfig.baseUrl;
-        this.fetchLogicInternal(this.baseConfig, lastEtag, retries, function (result) {
-            _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): result.status: " + (result === null || result === void 0 ? void 0 : result.status));
-            if (!result || result.status != FetchStatus.Fetched || ProjectConfig.compareEtags(lastEtag !== null && lastEtag !== void 0 ? lastEtag : '', result.eTag)) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): result.status != FetchStatus.Fetched or etags are the same. Returning null.");
-                callback(null);
-                return;
-            }
-            if (!result.responseBody) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): no response body. Returning null.");
-                callback(null);
-                return;
-            }
-            var newConfig = new ProjectConfig(new Date().getTime(), result.responseBody, result.eTag);
-            var preferences = newConfig.ConfigJSON[ConfigFile.Preferences];
-            if (!preferences) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): preferences is empty. Returning newConfig.");
-                callback(newConfig);
-                return;
-            }
-            var baseUrl = preferences[Preferences.BaseUrl];
-            // If the base_url is the same as the last called one, just return the response.
-            if (!baseUrl || baseUrl == calledBaseUrl) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): baseUrl OK. Returning newConfig.");
-                callback(newConfig);
-                return;
-            }
-            var redirect = preferences[Preferences.Redirect];
-            // If the base_url is overridden, and the redirect parameter is not 2 (force),
-            // the SDK should not redirect the calls and it just have to return the response.
-            if (options.baseUrlOverriden && redirect !== 2) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogic(): options.baseUrlOverriden && redirect !== 2.");
-                callback(newConfig);
-                return;
-            }
-            options.baseUrl = baseUrl;
-            if (redirect === 0) {
-                callback(newConfig);
-                return;
-            }
-            if (redirect === 1) {
-                options.logger.warn("Your dataGovernance parameter at ConfigCatClient initialization is not in sync " +
-                    "with your preferences on the ConfigCat Dashboard: " +
-                    "https://app.configcat.com/organization/data-governance. " +
-                    "Only Organization Admins can access this preference.");
-            }
-            if (retries >= 2) {
-                options.logger.error("Redirect loop during config.json fetch. Please contact [e-mail].");
-                callback(newConfig);
-                return;
-            }
-            _this.fetchLogic(options, lastEtag, ++retries, callback);
-            return;
+    ConfigServiceBase.prototype.refreshConfigCoreAsync = function (latestConfig) {
+        return __awaiter(this, void 0, void 0, function () {
+            var _a, fetchResult, newConfig, configContentHasChanged;
+            return __generator(this, function (_b) {
+                switch (_b.label) {
+                    case 0: return [4 /*yield*/, this.fetchAsync(latestConfig)];
+                    case 1:
+                        _a = _b.sent(), fetchResult = _a[0], newConfig = _a[1];
+                        configContentHasChanged = !ProjectConfig.equals(latestConfig, newConfig);
+                        if (!(newConfig && (configContentHasChanged || newConfig.Timestamp > latestConfig.Timestamp))) return [3 /*break*/, 3];
+                        return [4 /*yield*/, this.options.cache.set(this.options.getCacheKey(), newConfig)];
+                    case 2:
+                        _b.sent();
+                        this.onConfigUpdated(newConfig);
+                        if (configContentHasChanged) {
+                            this.onConfigChanged(newConfig);
+                        }
+                        return [2 /*return*/, [fetchResult, newConfig]];
+                    case 3: return [2 /*return*/, [fetchResult, latestConfig]];
+                }
+            });
         });
     };
-    ConfigServiceBase.prototype.fetchLogicInternal = function (options, lastEtag, retries, callback) {
+    ConfigServiceBase.prototype.onConfigUpdated = function (newConfig) { };
+    ConfigServiceBase.prototype.onConfigChanged = function (newConfig) {
+        this.options.logger.debug("config changed");
+        this.options.hooks.emit("configChanged", newConfig);
+    };
+    ConfigServiceBase.prototype.fetchAsync = function (lastConfig) {
         var _this = this;
-        this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): called.");
-        if (retries === 0) { // Only lock on the top-level calls, not on the recursive calls (config.json redirections).
-            this.fetchLogicCallbacks.push(callback);
-            if (this.fetchLogicCallbacks.length > 1) {
-                // The first fetchLogic call is already in progress.
-                this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): The first fetchLogic call is already in progress. this.fetchLogicCallbacks.length = " + this.fetchLogicCallbacks.length);
-                return;
-            }
-            this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): Calling fetchLogic");
-            this.configFetcher.fetchLogic(options, lastEtag, function (newProjectConfig) {
-                _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): fetchLogic() success, calling callbacks. this.fetchLogicCallbacks.length = " + _this.fetchLogicCallbacks.length);
-                while (_this.fetchLogicCallbacks.length) {
-                    var thisCallback = _this.fetchLogicCallbacks.pop();
-                    if (thisCallback) {
-                        _this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): fetchLogic() success, calling callback.");
-                        thisCallback(newProjectConfig);
-                    }
+        var _a;
+        return (_a = this.pendingFetch) !== null && _a !== void 0 ? _a : (this.pendingFetch = (function () { return __awaiter(_this, void 0, void 0, function () {
+            return __generator(this, function (_a) {
+                switch (_a.label) {
+                    case 0:
+                        _a.trys.push([0, , 2, 3]);
+                        return [4 /*yield*/, this.fetchLogicAsync(lastConfig)];
+                    case 1: return [2 /*return*/, _a.sent()];
+                    case 2:
+                        this.pendingFetch = null;
+                        return [7 /*endfinally*/];
+                    case 3: return [2 /*return*/];
                 }
             });
+        }); })());
+    };
+    ConfigServiceBase.prototype.fetchLogicAsync = function (lastConfig) {
+        var _a;
+        return __awaiter(this, void 0, void 0, function () {
+            var options, errorMessage, _b, response, configJson, err_1, errorMessage_1;
+            return __generator(this, function (_c) {
+                switch (_c.label) {
+                    case 0:
+                        options = this.options;
+                        options.logger.debug("ConfigServiceBase.fetchLogicAsync() - called.");
+                        _c.label = 1;
+                    case 1:
+                        _c.trys.push([1, 3, , 4]);
+                        return [4 /*yield*/, this.fetchRequestAsync((_a = lastConfig === null || lastConfig === void 0 ? void 0 : lastConfig.HttpETag) !== null && _a !== void 0 ? _a : null)];
+                    case 2:
+                        _b = _c.sent(), response = _b[0], configJson = _b[1];
+                        switch (response.statusCode) {
+                            case 200: // OK
+                                if (!configJson) {
+                                    errorMessage = "Fetch was successful but HTTP response was invalid";
+                                    options.logger.debug("ConfigServiceBase.fetchLogicAsync(): ".concat(errorMessage.charAt(0).toLowerCase()).concat(errorMessage.slice(1), ". Returning null."));
+                                    return [2 /*return*/, [FetchResult.error(errorMessage), null]];
+                                }
+                                options.logger.debug("ConfigServiceBase.fetchLogicAsync(): fetch was successful. Returning new config.");
+                                return [2 /*return*/, [FetchResult.success(response.body, response.eTag), new ProjectConfig(new Date().getTime(), configJson, response.eTag)]];
+                            case 304: // Not Modified
+                                if (!lastConfig) {
+                                    errorMessage = "HTTP response ".concat(response.statusCode, " ").concat(response.reasonPhrase, " was received when no config is cached locally");
+                                    options.logger.debug("ConfigServiceBase.fetchLogicAsync(): ".concat(errorMessage.charAt(0).toLowerCase()).concat(errorMessage.slice(1), ". Returning null."));
+                                    return [2 /*return*/, [FetchResult.error(errorMessage), null]];
+                                }
+                                options.logger.debug("ConfigServiceBase.fetchLogicAsync(): content was not modified. Returning last config with updated timestamp.");
+                                return [2 /*return*/, [FetchResult.notModified(), new ProjectConfig(new Date().getTime(), lastConfig.ConfigJSON, lastConfig.HttpETag)]];
+                            case 403: // Forbidden
+                            case 404: // Not Found
+                                errorMessage = "Double-check your SDK Key at https://app.configcat.com/sdkkey";
+                                options.logger.error(errorMessage);
+                                options.logger.debug("ConfigServiceBase.fetchLogicAsync(): fetch was unsuccessful. Returning last config (if any) with updated timestamp.");
+                                return [2 /*return*/, [FetchResult.error(errorMessage), lastConfig ? new ProjectConfig(new Date().getTime(), lastConfig.ConfigJSON, lastConfig.HttpETag) : null]];
+                            default:
+                                errorMessage = "Unexpected HTTP response was received: ".concat(response.statusCode, " ").concat(response.reasonPhrase);
+                                options.logger.error(errorMessage);
+                                options.logger.debug("ConfigServiceBase.fetchLogicAsync(): fetch was unsuccessful. Returning null.");
+                                return [2 /*return*/, [FetchResult.error(errorMessage), null]];
+                        }
+                        return [3 /*break*/, 4];
+                    case 3:
+                        err_1 = _c.sent();
+                        errorMessage_1 = err_1 instanceof FetchError
+                            ? err_1.message
+                            : "Unexpected error occurred during fetching.";
+                        options.logger.error(errorMessage_1, err_1);
+                        options.logger.debug("ConfigServiceBase.fetchLogicAsync(): fetch was unsuccessful. Returning null.");
+                        return [2 /*return*/, [FetchResult.error(errorMessage_1, err_1), null]];
+                    case 4: return [2 /*return*/];
+                }
+            });
+        });
+    };
+    ConfigServiceBase.prototype.fetchRequestAsync = function (lastETag, maxRetryCount) {
+        if (maxRetryCount === void 0) { maxRetryCount = 2; }
+        return __awaiter(this, void 0, void 0, function () {
+            var options, retryNumber, response, configJSON, preferences, baseUrl, redirect;
+            return __generator(this, function (_a) {
+                switch (_a.label) {
+                    case 0:
+                        options = this.options;
+                        options.logger.debug("ConfigServiceBase.fetchRequestAsync() - called.");
+                        retryNumber = 0;
+                        _a.label = 1;
+                    case 1:
+                        options.logger.debug("ConfigServiceBase.fetchRequestAsync(): calling fetchLogic()".concat(retryNumber > 0 ? ", retry ".concat(retryNumber, "/").concat(maxRetryCount) : ""));
+                        return [4 /*yield*/, this.configFetcher.fetchLogic(options, lastETag)];
+                    case 2:
+                        response = _a.sent();
+                        if (response.statusCode !== 200) {
+                            return [2 /*return*/, [response]];
+                        }
+                        if (!response.body) {
+                            options.logger.debug("ConfigServiceBase.fetchRequestAsync(): no response body.");
+                            return [2 /*return*/, [response]];
+                        }
+                        configJSON = void 0;
+                        try {
+                            configJSON = JSON.parse(response.body);
+                        }
+                        catch (_b) {
+                            options.logger.debug("ConfigServiceBase.fetchRequestAsync(): invalid response body.");
+                            return [2 /*return*/, [response]];
+                        }
+                        preferences = configJSON[ConfigFile.Preferences];
+                        if (!preferences) {
+                            options.logger.debug("ConfigServiceBase.fetchRequestAsync(): preferences is empty.");
+                            return [2 /*return*/, [response, configJSON]];
+                        }
+                        baseUrl = preferences[Preferences.BaseUrl];
+                        // If the base_url is the same as the last called one, just return the response.
+                        if (!baseUrl || baseUrl == options.baseUrl) {
+                            options.logger.debug("ConfigServiceBase.fetchRequestAsync(): baseUrl OK.");
+                            return [2 /*return*/, [response, configJSON]];
+                        }
+                        redirect = preferences[Preferences.Redirect];
+                        // If the base_url is overridden, and the redirect parameter is not 2 (force),
+                        // the SDK should not redirect the calls and it just have to return the response.
+                        if (options.baseUrlOverriden && redirect !== 2) {
+                            options.logger.debug("ConfigServiceBase.fetchRequestAsync(): options.baseUrlOverriden && redirect !== 2.");
+                            return [2 /*return*/, [response, configJSON]];
+                        }
+                        options.baseUrl = baseUrl;
+                        if (redirect === 0) {
+                            return [2 /*return*/, [response, configJSON]];
+                        }
+                        if (redirect === 1) {
+                            options.logger.warn("Your dataGovernance parameter at ConfigCatClient initialization is not in sync " +
+                                "with your preferences on the ConfigCat Dashboard: " +
+                                "https://app.configcat.com/organization/data-governance. " +
+                                "Only Organization Admins can access this preference.");
+                        }
+                        if (retryNumber >= maxRetryCount) {
+                            options.logger.error("Redirect loop during config.json fetch. Please contact [e-mail].");
+                            return [2 /*return*/, [response, configJSON]];
+                        }
+                        _a.label = 3;
+                    case 3:
+                        retryNumber++;
+                        return [3 /*break*/, 1];
+                    case 4: return [2 /*return*/];
+                }
+            });
+        });
+    };
+    Object.defineProperty(ConfigServiceBase.prototype, "isOfflineExactly", {
+        get: function () {
+            return this.status === ConfigServiceStatus.Offline;
+        },
+        enumerable: false,
+        configurable: true
+    });
+    Object.defineProperty(ConfigServiceBase.prototype, "isOffline", {
+        get: function () {
+            return this.status !== ConfigServiceStatus.Online;
+        },
+        enumerable: false,
+        configurable: true
+    });
+    ConfigServiceBase.prototype.setOnlineCore = function () { };
+    ConfigServiceBase.prototype.setOnline = function () {
+        if (this.status === ConfigServiceStatus.Offline) {
+            this.setOnlineCore();
+            this.status = ConfigServiceStatus.Online;
+            this.logStatusChange(this.status);
         }
-        else {
-            // Recursive calls should call the fetchLogic as is.
-            this.baseConfig.logger.debug("ConfigServiceBase.fetchLogicInternal(): calling fetchLogic(), recursive call. retries = " + retries);
-            this.configFetcher.fetchLogic(options, lastEtag, callback);
+        else if (this.disposed) {
+            this.logDisposedWarning("setOnline");
         }
     };
+    ConfigServiceBase.prototype.setOfflineCore = function () { };
+    ConfigServiceBase.prototype.setOffline = function () {
+        if (this.status == ConfigServiceStatus.Online) {
+            this.setOfflineCore();
+            this.status = ConfigServiceStatus.Offline;
+            this.logStatusChange(this.status);
+        }
+        else if (this.disposed) {
+            this.logDisposedWarning("setOnline");
+        }
+    };
+    ConfigServiceBase.prototype.logStatusChange = function (status) {
+        var _a;
+        this.options.logger.debug("Switched to ".concat((_a = ConfigServiceStatus[status]) === null || _a === void 0 ? void 0 : _a.toUpperCase(), " mode."));
+    };
+    ConfigServiceBase.prototype.logOfflineModeWarning = function () {
+        this.options.logger.warn("Client is in offline mode, it can't initiate HTTP calls.");
+    };
+    ConfigServiceBase.prototype.logDisposedWarning = function (methodName) {
+        this.options.logger.warn("Client has already been disposed, thus ".concat(methodName, "() has no effect."));
+    };
     return ConfigServiceBase;
 }());
 export { ConfigServiceBase };

lib/esm/index.js

 import { ConfigCatClient } from "./ConfigCatClient";
-import { AutoPollOptions, ManualPollOptions, LazyLoadOptions } from "./ConfigCatClientOptions";
-import { ConfigCatConsoleLogger } from "./ConfigCatLogger";
+import { AutoPollOptions, LazyLoadOptions, ManualPollOptions, PollingMode } from "./ConfigCatClientOptions";
+import { ConfigCatConsoleLogger, LogLevel } from "./ConfigCatLogger";
 import { setupPolyfills } from "./Polyfills";
 setupPolyfills();
 /**
+ * Returns an instance of ConfigCatClient for the specified SDK Key.
+ * @remarks This method returns a single, shared instance per each distinct SDK Key.
+ * That is, a new client object is created only when there is none available for the specified SDK Key.
+ * Otherwise, the already created instance is returned (in which case the 'pollingMode', 'options' and 'configCatKernel' arguments are ignored).
+ * So, please keep in mind that when you make multiple calls to this method using the same SDK Key, you may end up with multiple references to the same client object.
+ * @param sdkKey SDK Key (a.k.a ApiKey) to access configuration
+ * @param pollingMode The polling mode to use
+ * @param options Options for the specified polling mode
+ */
+export function getClient(sdkKey, pollingMode, options, configCatKernel) {
+    return ConfigCatClient.get(sdkKey, pollingMode, options, configCatKernel);
+}
+/**
+ * Disposes all existing ConfigCatClient instances.
+ */
+export function disposeAllClients() {
+    ConfigCatClient.disposeAll();
+}
+/**
  * Create an instance of ConfigCatClient and setup AutoPoll mode
  * @param {string} apiKey - ApiKey to access your configuration.
  * @param config - Configuration for autoPoll mode
+ * @deprecated This function is obsolete and will be removed from the public API in a future major version. To obtain a ConfigCatClient instance with auto polling for a specific SDK Key, please use the 'getClient(sdkKey, PollingMode.AutoPoll, options, ...)' format.
  */
 export function createClientWithAutoPoll(apiKey, configCatKernel, options) {
-    return new ConfigCatClient(new AutoPollOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache), configCatKernel);
+    return new ConfigCatClient(new AutoPollOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache, configCatKernel.eventEmitterFactory), configCatKernel);
 }
@@ -18,5 +38,6 @@ /**
  * @param config - Configuration for manualPoll mode
+ * @deprecated This function is obsolete and will be removed from the public API in a future major version. To obtain a ConfigCatClient instance with manual polling for a specific SDK Key, please use the 'getClient(sdkKey, PollingMode.ManualPoll, options, ...)' format.
  */
 export function createClientWithManualPoll(apiKey, configCatKernel, options) {
-    return new ConfigCatClient(new ManualPollOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache), configCatKernel);
+    return new ConfigCatClient(new ManualPollOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache, configCatKernel.eventEmitterFactory), configCatKernel);
 }
@@ -27,9 +48,10 @@ /**
  * @param config - Configuration for lazyLoad mode
+ * @deprecated This function is obsolete and will be removed from the public API in a future major version. To obtain a ConfigCatClient instance with lazy loading for a specific SDK Key, please use the 'getClient(sdkKey, PollingMode.LazyLoad, options, ...)' format.
  */
 export function createClientWithLazyLoad(apiKey, configCatKernel, options) {
-    return new ConfigCatClient(new LazyLoadOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache), configCatKernel);
+    return new ConfigCatClient(new LazyLoadOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache, configCatKernel.eventEmitterFactory), configCatKernel);
 }
 /**
  * Create an instance of ConfigCatConsoleLogger
- * @param {LogLevel} logLevel - Specifies message's filtering to output for the CofigCatConsoleLogger.
+ * @param {LogLevel} logLevel - Specifies message's filtering to output for the ConfigCatConsoleLogger.
  */
@@ -39,37 +61,15 @@ export function createConsoleLogger(logLevel) {
 }
-export var LogLevel;
-(function (LogLevel) {
-    LogLevel[LogLevel["Debug"] = 4] = "Debug";
-    LogLevel[LogLevel["Info"] = 3] = "Info";
-    LogLevel[LogLevel["Warn"] = 2] = "Warn";
-    LogLevel[LogLevel["Error"] = 1] = "Error";
-    LogLevel[LogLevel["Off"] = -1] = "Off";
-})(LogLevel || (LogLevel = {}));
-export var FetchStatus;
-(function (FetchStatus) {
-    FetchStatus[FetchStatus["Fetched"] = 0] = "Fetched";
-    FetchStatus[FetchStatus["NotModified"] = 1] = "NotModified";
-    FetchStatus[FetchStatus["Errored"] = 2] = "Errored";
-})(FetchStatus || (FetchStatus = {}));
-var FetchResult = /** @class */ (function () {
-    function FetchResult(status, responseBody, eTag) {
-        this.status = status;
-        this.responseBody = responseBody;
-        this.eTag = eTag;
-    }
-    FetchResult.success = function (responseBody, eTag) {
-        return new FetchResult(FetchStatus.Fetched, responseBody, eTag);
-    };
-    FetchResult.notModified = function () {
-        return new FetchResult(FetchStatus.NotModified, "");
-    };
-    FetchResult.error = function () {
-        return new FetchResult(FetchStatus.Errored, "");
-    };
-    return FetchResult;
-}());
-export { FetchResult };
-export { ProjectConfig } from "./ProjectConfig";
-export { OptionsBase, DataGovernance } from "./ConfigCatClientOptions";
+export { FetchStatus, FetchResult, FetchError } from './ConfigFetcher';
+export { OptionsBase } from "./ConfigCatClientOptions";
+export { InMemoryCache } from "./Cache";
+/* Public types for end users */
+// List types here which are part of the public API of platform-specific SDKs, thus, should be exposed to end users.
+// These exports should be re-exported in the entry module of each platform-specific SDK!
+export { PollingMode };
+export { DataGovernance } from "./ConfigCatClientOptions";
+export { LogLevel };
+export { ProjectConfig, RolloutRule, RolloutPercentageItem, Setting } from "./ProjectConfig";
+export { SettingKeyValue } from "./ConfigCatClient";
 export { User } from "./RolloutEvaluator";
 export { FlagOverrides, MapOverrideDataSource, OverrideBehaviour } from "./FlagOverrides";
+export { RefreshResult } from "./ConfigServiceBase";

lib/esm/LazyLoadConfigService.js

@@ -1,58 +0,10 @@
-var __extends = (this && this.__extends) || (function () {
-    var extendStatics = function (d, b) {
-        extendStatics = Object.setPrototypeOf ||
-            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
-            function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
-        return extendStatics(d, b);
-    };
-    return function (d, b) {
-        if (typeof b !== "function" && b !== null)
-            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
-        extendStatics(d, b);
-        function __() { this.constructor = d; }
-        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
-    };
-})();
-var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
-    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
-    return new (P || (P = Promise))(function (resolve, reject) {
-        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
-        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
-        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
-        step((generator = generator.apply(thisArg, _arguments || [])).next());
-    });
-};
-var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
-    function verb(n) { return function (v) { return step([n, v]); }; }
-    function step(op) {
-        if (f) throw new TypeError("Generator is already executing.");
-        while (_) try {
-            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
-            if (y = 0, t) op = [op[0] & 2, t.value];
-            switch (op[0]) {
-                case 0: case 1: t = op; break;
-                case 4: _.label++; return { value: op[1], done: false };
-                case 5: _.label++; y = op[1]; op = [0]; continue;
-                case 7: op = _.ops.pop(); _.trys.pop(); continue;
-                default:
-                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
-                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
-                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
-                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
-                    if (t[2]) _.ops.pop();
-                    _.trys.pop(); continue;
-            }
-            op = body.call(thisArg, _);
-        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
-        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
-    }
-};
+import { __awaiter, __extends, __generator } from "tslib";
 import { ConfigServiceBase } from "./ConfigServiceBase";
+import { ProjectConfig } from "./ProjectConfig";
 var LazyLoadConfigService = /** @class */ (function (_super) {
     __extends(LazyLoadConfigService, _super);
-    function LazyLoadConfigService(configFetcher, config) {
-        var _this = _super.call(this, configFetcher, config) || this;
-        _this.cacheTimeToLiveSeconds = config.cacheTimeToLiveSeconds;
+    function LazyLoadConfigService(configFetcher, options) {
+        var _this = _super.call(this, configFetcher, options) || this;
+        _this.cacheTimeToLiveSeconds = options.cacheTimeToLiveSeconds;
+        options.hooks.emit("clientReady");
         return _this;
@@ -62,19 +14,29 @@ }
         return __awaiter(this, void 0, void 0, function () {
-            var p;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
+            function logExpired(logger, appendix) {
+                if (appendix === void 0) { appendix = ""; }
+                logger.debug("LazyLoadConfigService.getConfig(): cache is empty or expired".concat(appendix, "."));
+            }
+            var config;
+            var _a;
+            return __generator(this, function (_b) {
+                switch (_b.label) {
                     case 0:
-                        this.baseConfig.logger.debug("LazyLoadConfigService.getConfig() called.");
-                        return [4 /*yield*/, this.baseConfig.cache.get(this.baseConfig.getCacheKey())];
+                        this.options.logger.debug("LazyLoadConfigService.getConfig() called.");
+                        return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
                     case 1:
-                        p = _a.sent();
-                        if (p && p.Timestamp + (this.cacheTimeToLiveSeconds * 1000) > new Date().getTime()) {
-                            this.baseConfig.logger.debug("LazyLoadConfigService.getConfig(): cache is valid, returning from cache.");
-                            return [2 /*return*/, p];
-                        }
-                        else {
-                            this.baseConfig.logger.debug("LazyLoadConfigService.getConfig(): cache is empty or expired, calling refreshLogicBaseAsync().");
-                            return [2 /*return*/, this.refreshLogicBaseAsync(p)];
-                        }
-                        return [2 /*return*/];
+                        config = _b.sent();
+                        if (!ProjectConfig.isExpired(config, this.cacheTimeToLiveSeconds * 1000)) return [3 /*break*/, 5];
+                        if (!!this.isOffline) return [3 /*break*/, 3];
+                        logExpired(this.options.logger, ", calling refreshConfigCoreAsync()");
+                        return [4 /*yield*/, this.refreshConfigCoreAsync(config)];
+                    case 2:
+                        _a = _b.sent(), config = _a[1];
+                        return [3 /*break*/, 4];
+                    case 3:
+                        logExpired(this.options.logger);
+                        _b.label = 4;
+                    case 4: return [2 /*return*/, config];
+                    case 5:
+                        this.options.logger.debug("LazyLoadConfigService.getConfig(): cache is valid, returning from cache.");
+                        return [2 /*return*/, config];
                 }
@@ -86,12 +48,5 @@ });
         return __awaiter(this, void 0, void 0, function () {
-            var p;
             return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0:
-                        this.baseConfig.logger.debug("LazyLoadConfigService.refreshConfigAsync() called.");
-                        return [4 /*yield*/, this.baseConfig.cache.get(this.baseConfig.getCacheKey())];
-                    case 1:
-                        p = _a.sent();
-                        return [2 /*return*/, this.refreshLogicBaseAsync(p)];
-                }
+                this.options.logger.debug("LazyLoadConfigService.refreshConfigAsync() called.");
+                return [2 /*return*/, _super.prototype.refreshConfigAsync.call(this)];
             });
@@ -98,0 +53,0 @@ });

lib/esm/Polyfills.js

 export function setupPolyfills() {
-    if (!Object.fromEntries) {
-        Object.fromEntries = function (entries) {
-            if (!entries || !entries[Symbol.iterator]) {
-                throw new Error('Object.fromEntries() requires a single iterable argument');
-            }
-            var obj = {};
-            for (var _i = 0, entries_1 = entries; _i < entries_1.length; _i++) {
-                var _a = entries_1[_i], key = _a[0], value = _a[1];
-                obj[key] = value;
-            }
-            return obj;
-        };
+    // Object.values
+    if (typeof Object.values === "undefined") {
+        Object.values = ObjectValuesPolyfill;
     }
+    // Object.entries
+    if (typeof Object.entries === "undefined") {
+        Object.entries = ObjectEntriesPolyfill;
+    }
+    // Object.fromEntries
+    if (typeof Object.fromEntries === "undefined") {
+        Object.fromEntries = ObjectFromEntriesPolyfill;
+    }
+    // WeakRef
+    if (typeof WeakRef === "undefined") {
+        // There's no way to correctly polyfill WeakRef (https://stackoverflow.com/a/69971312/8656352),
+        // so we just polyfill its API (which means falling back on strong references in this case).
+        WeakRef = getWeakRefFallback();
+    }
 }
+export function ObjectValuesPolyfill(o) {
+    var result = [];
+    for (var _i = 0, _a = Object.keys(o); _i < _a.length; _i++) {
+        var key = _a[_i];
+        result.push(o[key]);
+    }
+    return result;
+}
+export function ObjectEntriesPolyfill(o) {
+    var result = [];
+    for (var _i = 0, _a = Object.keys(o); _i < _a.length; _i++) {
+        var key = _a[_i];
+        result.push([key, o[key]]);
+    }
+    return result;
+}
+export function ObjectFromEntriesPolyfill(entries) {
+    var _a;
+    var result = {};
+    if (Array.isArray(entries)) {
+        for (var _i = 0, entries_1 = entries; _i < entries_1.length; _i++) {
+            var _b = entries_1[_i], key = _b[0], value = _b[1];
+            result[key] = value;
+        }
+    }
+    else if (typeof Symbol !== "undefined" && (entries === null || entries === void 0 ? void 0 : entries[Symbol.iterator])) {
+        var iterator = entries[Symbol.iterator]();
+        var element = void 0, done = void 0;
+        while ((_a = iterator.next(), element = _a.value, done = _a.done, !done)) {
+            var key = element[0], value = element[1];
+            result[key] = value;
+        }
+    }
+    else {
+        throw new Error('Object.fromEntries() requires a single iterable argument');
+    }
+    return result;
+}
+export function getWeakRefFallback() {
+    var WeakRef = function (target) {
+        this.target = target;
+    };
+    WeakRef.prototype.deref = function () {
+        return this.target;
+    };
+    WeakRef.isFallback = true;
+    return WeakRef;
+}
+export var isWeakRefAvailable = function () { return typeof WeakRef === "function" && !WeakRef.hasOwnProperty("isFallback"); };

lib/esm/ProjectConfig.js

@@ -0,5 +1,10 @@
+// NOTE: No instance methods should be added to this class!
+// Flawed ICache implementations may erase the prototype information (when serialization is involved),
+// which would lead to "... is not a function" errors in the case of instance methods.
+// (As a matter of fact, this type should have been defined as an interface to prevent such complications but
+// we can't really change this any more because this would be a too dangerous breaking change at this point.)
 var ProjectConfig = /** @class */ (function () {
     function ProjectConfig(timeStamp, jsonConfig, httpETag) {
         this.Timestamp = timeStamp;
-        this.ConfigJSON = JSON.parse(jsonConfig);
+        this.ConfigJSON = typeof jsonConfig === "string" ? JSON.parse(jsonConfig) : jsonConfig;
         this.HttpETag = httpETag;
@@ -11,5 +16,14 @@ }
     ProjectConfig.equals = function (projectConfig1, projectConfig2) {
-        if (!projectConfig1 || !projectConfig2)
+        if (!projectConfig1) {
+            // If both configs are null, we consider them equal.
+            return !projectConfig2;
+        }
+        if (!projectConfig2) {
             return false;
-        return this.compareEtags(projectConfig1.HttpETag, projectConfig2.HttpETag);
+        }
+        // When both ETags are available, we don't need to check the JSON content
+        // (because of how HTTP ETags work - see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag).
+        return !!projectConfig1.HttpETag && !!projectConfig2.HttpETag
+            ? this.compareEtags(projectConfig1.HttpETag, projectConfig2.HttpETag)
+            : JSON.stringify(projectConfig1.ConfigJSON) === JSON.stringify(projectConfig2.ConfigJSON);
     };
@@ -28,2 +42,5 @@ ProjectConfig.compareEtags = function (etag1, etag2) {
     };
+    ProjectConfig.isExpired = function (projectConfig, expirationMs) {
+        return !projectConfig || projectConfig.Timestamp + expirationMs < new Date().getTime();
+    };
     return ProjectConfig;
@@ -30,0 +47,0 @@ }());

lib/esm/RolloutEvaluator.js

@@ -0,4 +1,5 @@
+import { RolloutPercentageItem, RolloutRule } from "./ProjectConfig";
+import * as semver from "./Semver";
 import { sha1 } from "./Sha1";
-import * as semver from "./Semver";
-import { isUndefined } from "./Utils";
+import { errorToString, getTimestampAsDate, isUndefined } from "./Utils";
 /** Object for variation evaluation */
@@ -21,11 +22,4 @@ var User = /** @class */ (function () {
     }
-    RolloutEvaluator.prototype.Evaluate = function (settings, key, defaultValue, user, defaultVariationId) {
+    RolloutEvaluator.prototype.Evaluate = function (setting, key, defaultValue, user, remoteConfig) {
         this.logger.debug("RolloutEvaluator.Evaluate() called.");
-        if (!settings[key]) {
-            var s = "Evaluating getValue('" + key + "') failed. Returning default value: '" + defaultValue + "'.";
-            s += " Here are the available keys: {" + Object.keys(settings).join() + "}.";
-            this.logger.error(s);
-            return { Value: defaultValue, VariationId: defaultVariationId };
-        }
-        var featureFlag = settings[key];
         var eLog = new EvaluateLogger();
@@ -35,39 +29,44 @@ eLog.User = user;
         eLog.ReturnValue = defaultValue;
-        var result = new EvaluateResult();
-        result.EvaluateLog = eLog;
-        if (user) {
-            result = this.EvaluateRules(featureFlag.rolloutRules, user, eLog);
-            if (result.ValueAndVariationId == null) {
-                result.ValueAndVariationId = this.EvaluateVariations(featureFlag.rolloutPercentageItems, key, user);
-                if (result.ValueAndVariationId) {
-                    result.EvaluateLog.ReturnValue = result.ValueAndVariationId.Value;
+        var result;
+        try {
+            if (user) {
+                // evaluate comparison-based rules
+                result = this.EvaluateRules(setting.rolloutRules, user, eLog);
+                if (result !== null) {
+                    eLog.ReturnValue = result.value;
+                    return evaluationDetailsFromEvaluateResult(key, result, getTimestampAsDate(remoteConfig), user);
                 }
-                if (featureFlag.rolloutPercentageItems.length > 0) {
-                    result.EvaluateLog.OpAppendLine("Evaluating % options => " + (result.ValueAndVariationId == null ? "user not targeted" : "user targeted"));
+                // evaluate percentage-based rules
+                result = this.EvaluatePercentageRules(setting.rolloutPercentageItems, key, user);
+                if (setting.rolloutPercentageItems && setting.rolloutPercentageItems.length > 0) {
+                    eLog.OpAppendLine("Evaluating % options => " + (!result ? "user not targeted" : "user targeted"));
                 }
+                if (result !== null) {
+                    eLog.ReturnValue = result.value;
+                    return evaluationDetailsFromEvaluateResult(key, result, getTimestampAsDate(remoteConfig), user);
+                }
             }
-        }
-        else {
-            if ((featureFlag.rolloutRules && featureFlag.rolloutRules.length > 0) ||
-                (featureFlag.rolloutPercentageItems && featureFlag.rolloutPercentageItems.length > 0)) {
-                var s = "Evaluating getValue('" + key + "'). ";
-                s += "UserObject missing! You should pass a UserObject to getValue(), in order to make targeting work properly. ";
-                s += "Read more: https://configcat.com/docs/advanced/user-object";
-                this.logger.warn(s);
+            else {
+                if ((setting.rolloutRules && setting.rolloutRules.length > 0) ||
+                    (setting.rolloutPercentageItems && setting.rolloutPercentageItems.length > 0)) {
+                    var s = "Evaluating getValue('" + key + "'). ";
+                    s += "UserObject missing! You should pass a UserObject to getValue(), in order to make targeting work properly. ";
+                    s += "Read more: https://configcat.com/docs/advanced/user-object";
+                    this.logger.warn(s);
+                }
             }
-        }
-        if (result.ValueAndVariationId == null) {
-            result.ValueAndVariationId = {
-                Value: featureFlag.value,
-                VariationId: featureFlag.variationId,
+            // regular evaluate
+            result = {
+                value: setting.value,
+                variationId: setting.variationId
             };
-            result.EvaluateLog.ReturnValue = result.ValueAndVariationId.Value;
+            eLog.ReturnValue = result.value;
+            return evaluationDetailsFromEvaluateResult(key, result, getTimestampAsDate(remoteConfig), user);
         }
-        this.logger.info(result.EvaluateLog.GetLog());
-        return result.ValueAndVariationId;
+        finally {
+            this.logger.info(eLog.GetLog());
+        }
     };
     RolloutEvaluator.prototype.EvaluateRules = function (rolloutRules, user, eLog) {
         this.logger.debug("RolloutEvaluator.EvaluateRules() called.");
-        var result = new EvaluateResult();
-        result.ValueAndVariationId = null;
         if (rolloutRules && rolloutRules.length > 0) {
@@ -85,2 +84,7 @@ var _loop_1 = function (i) {
                 }
+                var result = {
+                    value: rule.value,
+                    variationId: rule.variationId,
+                    matchedRule: rule
+                };
                 switch (comparator) {
@@ -93,8 +97,2 @@ case 0: // is one of
                                 eLog.OpAppendLine(log);
-                                result.ValueAndVariationId = {
-                                    Value: rule.value,
-                                    VariationId: rule.variationId
-                                };
-                                eLog.ReturnValue = result.ValueAndVariationId.Value;
-                                result.EvaluateLog = eLog;
                                 return { value: result };
@@ -114,8 +112,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -129,8 +121,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -144,8 +130,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -164,8 +144,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -184,8 +158,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -201,8 +169,2 @@ }
                                 eLog.OpAppendLine(log);
-                                result.ValueAndVariationId = {
-                                    Value: rule.value,
-                                    VariationId: rule.variationId
-                                };
-                                eLog.ReturnValue = result.ValueAndVariationId.Value;
-                                result.EvaluateLog = eLog;
                                 return { value: result };
@@ -222,8 +184,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -245,9 +201,8 @@ }
         }
-        result.EvaluateLog = eLog;
-        return result;
+        return null;
     };
-    RolloutEvaluator.prototype.EvaluateVariations = function (rolloutPercentageItems, key, user) {
+    RolloutEvaluator.prototype.EvaluatePercentageRules = function (rolloutPercentageItems, key, user) {
         this.logger.debug("RolloutEvaluator.EvaluateVariations() called.");
         if (rolloutPercentageItems && rolloutPercentageItems.length > 0) {
-            var hashCandidate = key + ((user.identifier === null || user.identifier === undefined) ? '' : user.identifier);
+            var hashCandidate = key + ((user.identifier === null || user.identifier === void 0) ? '' : user.identifier);
             var hashValue = sha1(hashCandidate).substring(0, 7);
@@ -257,8 +212,9 @@ var hashScale = parseInt(hashValue, 16) % 100;
             for (var i = 0; i < rolloutPercentageItems.length; i++) {
-                var variation = rolloutPercentageItems[i];
-                bucket += +variation.percentage;
+                var percentageRule = rolloutPercentageItems[i];
+                bucket += +percentageRule.percentage;
                 if (hashScale < bucket) {
                     return {
-                        Value: variation.value,
-                        VariationId: variation.variationId
+                        value: percentageRule.value,
+                        variationId: percentageRule.variationId,
+                        matchedRule: percentageRule
                     };
@@ -420,12 +376,2 @@ }
 export { RolloutEvaluator };
-var ValueAndVariationId = /** @class */ (function () {
-    function ValueAndVariationId() {
-    }
-    return ValueAndVariationId;
-}());
-var EvaluateResult = /** @class */ (function () {
-    function EvaluateResult() {
-    }
-    return EvaluateResult;
-}());
 var EvaluateLogger = /** @class */ (function () {
@@ -446,1 +392,121 @@ function EvaluateLogger() {
 }());
+/* Helper functions */
+function evaluationDetailsFromEvaluateResult(key, evaluateResult, fetchTime, user) {
+    return {
+        key: key,
+        value: evaluateResult.value,
+        variationId: evaluateResult.variationId,
+        fetchTime: fetchTime,
+        user: user,
+        isDefaultValue: false,
+        matchedEvaluationRule: evaluateResult.matchedRule instanceof RolloutRule ? evaluateResult.matchedRule : void 0,
+        matchedEvaluationPercentageRule: evaluateResult.matchedRule instanceof RolloutPercentageItem ? evaluateResult.matchedRule : void 0,
+    };
+}
+export function evaluationDetailsFromDefaultValue(key, defaultValue, fetchTime, user, errorMessage, errorException) {
+    return {
+        key: key,
+        value: defaultValue,
+        fetchTime: fetchTime,
+        user: user,
+        isDefaultValue: true,
+        errorMessage: errorMessage,
+        errorException: errorException
+    };
+}
+export function evaluationDetailsFromDefaultVariationId(key, defaultVariationId, fetchTime, user, errorMessage, errorException) {
+    return {
+        key: key,
+        value: null,
+        variationId: defaultVariationId,
+        fetchTime: fetchTime,
+        user: user,
+        isDefaultValue: true,
+        errorMessage: errorMessage,
+        errorException: errorException
+    };
+}
+export function evaluate(evaluator, settings, key, defaultValue, user, remoteConfig, logger) {
+    var errorMessage;
+    if (!settings) {
+        errorMessage = "config.json is not present. Returning default value: '".concat(defaultValue, "'.");
+        logger.error(errorMessage);
+        return evaluationDetailsFromDefaultValue(key, defaultValue, getTimestampAsDate(remoteConfig), user, errorMessage);
+    }
+    var setting = settings[key];
+    if (!setting) {
+        errorMessage = "Evaluating '".concat(key, "' failed (key was not found in config.json). Returning default value: '").concat(defaultValue, "'. These are the available keys: ").concat(keysToString(settings), ".");
+        logger.error(errorMessage);
+        return evaluationDetailsFromDefaultValue(key, defaultValue, getTimestampAsDate(remoteConfig), user, errorMessage);
+    }
+    ensureAllowedDefaultValue(defaultValue);
+    var evaluationDetails = evaluator.Evaluate(setting, key, defaultValue, user, remoteConfig);
+    if (defaultValue !== null && defaultValue !== void 0 && typeof defaultValue !== typeof evaluationDetails.value) {
+        throw new Error("The type of a setting must match the type of the given default value.\nThe setting's type was ".concat(typeof defaultValue, ", the given default value's type was ").concat(typeof evaluationDetails.value, ".\nPlease pass a corresponding default value type."));
+    }
+    return evaluationDetails;
+}
+export function evaluateVariationId(evaluator, settings, key, defaultVariationId, user, remoteConfig, logger) {
+    var errorMessage;
+    if (!settings) {
+        errorMessage = "config.json is not present. Returning default variationId: '".concat(defaultVariationId, "'.");
+        logger.error(errorMessage);
+        return evaluationDetailsFromDefaultVariationId(key, defaultVariationId, getTimestampAsDate(remoteConfig), user, errorMessage);
+    }
+    var setting = settings[key];
+    if (!setting) {
+        errorMessage = "Evaluating '".concat(key, "' failed (key was not found in config.json). Returning default variationId: '").concat(defaultVariationId, "'. These are the available keys: ").concat(keysToString(settings), ".");
+        logger.error(errorMessage);
+        return evaluationDetailsFromDefaultVariationId(key, defaultVariationId, getTimestampAsDate(remoteConfig), user, errorMessage);
+    }
+    return evaluator.Evaluate(setting, key, null, user, remoteConfig, defaultVariationId);
+}
+function evaluateAllCore(evaluator, settings, user, remoteConfig, logger, getDetailsForError) {
+    var errors;
+    if (!checkSettingsAvailable(settings, logger, ", returning empty array")) {
+        return [[], errors];
+    }
+    var evaluationDetailsArray = [];
+    var index = 0;
+    for (var _i = 0, _a = Object.entries(settings); _i < _a.length; _i++) {
+        var _b = _a[_i], key = _b[0], setting = _b[1];
+        var evaluationDetails = void 0;
+        try {
+            evaluationDetails = evaluator.Evaluate(setting, key, null, user, remoteConfig);
+        }
+        catch (err) {
+            errors !== null && errors !== void 0 ? errors : (errors = []);
+            errors.push(err);
+            evaluationDetails = getDetailsForError(key, getTimestampAsDate(remoteConfig), user, err);
+        }
+        evaluationDetailsArray[index++] = evaluationDetails;
+    }
+    return [evaluationDetailsArray, errors];
+}
+export function evaluateAll(evaluator, settings, user, remoteConfig, logger) {
+    return evaluateAllCore(evaluator, settings, user, remoteConfig, logger, function (key, fetchTime, user, err) { return evaluationDetailsFromDefaultValue(key, null, fetchTime, user, errorToString(err), err); });
+}
+export function evaluateAllVariationIds(evaluator, settings, user, remoteConfig, logger) {
+    return evaluateAllCore(evaluator, settings, user, remoteConfig, logger, function (key, fetchTime, user, err) { return evaluationDetailsFromDefaultVariationId(key, null, fetchTime, user, errorToString(err), err); });
+}
+export function checkSettingsAvailable(settings, logger, appendix) {
+    if (appendix === void 0) { appendix = ""; }
+    if (!settings) {
+        logger.error("config.json is not present".concat(appendix));
+        return false;
+    }
+    return true;
+}
+export function ensureAllowedDefaultValue(value) {
+    if (value === null || value === void 0) {
+        return;
+    }
+    var type = typeof value;
+    if (type === "boolean" || type === "number" || type === "string") {
+        return;
+    }
+    throw new Error("The default value must be boolean, number, string, null or undefined.");
+}
+function keysToString(settings) {
+    return Object.keys(settings).join();
+}

lib/esm/Semver.js

@@ -30,3 +30,3 @@ var numeric = /^[0-9]+$/;
     src[index] = value;
-    re[index] = new RegExp(value, undefined);
+    re[index] = new RegExp(value);
 };
@@ -164,9 +164,9 @@ createToken('NUMERICIDENTIFIER', '0|[1-9]\\d*');
             var b = other.prerelease[i];
-            if (a === undefined && b === undefined) {
+            if (a === void 0 && b === void 0) {
                 return 0;
             }
-            else if (b === undefined) {
+            else if (b === void 0) {
                 return 1;
             }
-            else if (a === undefined) {
+            else if (a === void 0) {
                 return -1;
@@ -190,9 +190,9 @@ }
             var b = other.build[i];
-            if (a === undefined && b === undefined) {
+            if (a === void 0 && b === void 0) {
                 return 0;
             }
-            else if (b === undefined) {
+            else if (b === void 0) {
                 return 1;
             }
-            else if (a === undefined) {
+            else if (a === void 0) {
                 return -1;
@@ -199,0 +199,0 @@ }

lib/esm/Utils.js

 import { ConfigFile, Setting } from "./ProjectConfig";
-export var isUndefined = function (comp) { return comp === undefined; };
+export var isUndefined = function (comp) { return comp === void 0; };
+export function delay(delayMs, obtainCancel) {
+    var timerId;
+    var promise = new Promise(function (resolve) { return timerId = setTimeout(resolve, delayMs); });
+    obtainCancel === null || obtainCancel === void 0 ? void 0 : obtainCancel(function () { return clearTimeout(timerId); });
+    return promise;
+}
+;
 export function getSettingsFromConfig(json) {
-    if (!json) {
-        return {};
-    }
     return Object.fromEntries(Object.entries(json[ConfigFile.FeatureFlags]).map(function (_a) {
@@ -12,1 +16,10 @@ var key = _a[0], value = _a[1];
 }
+export function getTimestampAsDate(projectConfig) {
+    return projectConfig ? new Date(projectConfig.Timestamp) : void 0;
+}
+export function errorToString(err, includeStackTrace) {
+    if (includeStackTrace === void 0) { includeStackTrace = false; }
+    return err instanceof Error
+        ? includeStackTrace && err.stack ? err.stack : err.toString()
+        : err + "";
+}

lib/index.d.ts

@@ -1,8 +0,24 @@
-import { IConfigCatClient } from "./ConfigCatClient";
-import { IOptions, OptionsBase } from "./ConfigCatClientOptions";
-import { ProjectConfig } from "./ProjectConfig";
+import { IConfigCatClient, IConfigCatKernel } from "./ConfigCatClient";
+import { IAutoPollOptions, ILazyLoadingOptions, IManualPollOptions, OptionsForPollingMode, PollingMode } from "./ConfigCatClientOptions";
+import { IConfigCatLogger, LogLevel } from "./ConfigCatLogger";
 /**
+ * Returns an instance of ConfigCatClient for the specified SDK Key.
+ * @remarks This method returns a single, shared instance per each distinct SDK Key.
+ * That is, a new client object is created only when there is none available for the specified SDK Key.
+ * Otherwise, the already created instance is returned (in which case the 'pollingMode', 'options' and 'configCatKernel' arguments are ignored).
+ * So, please keep in mind that when you make multiple calls to this method using the same SDK Key, you may end up with multiple references to the same client object.
+ * @param sdkKey SDK Key (a.k.a ApiKey) to access configuration
+ * @param pollingMode The polling mode to use
+ * @param options Options for the specified polling mode
+ */
+export declare function getClient<TMode extends PollingMode>(sdkKey: string, pollingMode: TMode, options: OptionsForPollingMode<TMode> | undefined | null, configCatKernel: IConfigCatKernel): IConfigCatClient;
+/**
+ * Disposes all existing ConfigCatClient instances.
+ */
+export declare function disposeAllClients(): void;
+/**
  * Create an instance of ConfigCatClient and setup AutoPoll mode
  * @param {string} apiKey - ApiKey to access your configuration.
  * @param config - Configuration for autoPoll mode
+ * @deprecated This function is obsolete and will be removed from the public API in a future major version. To obtain a ConfigCatClient instance with auto polling for a specific SDK Key, please use the 'getClient(sdkKey, PollingMode.AutoPoll, options, ...)' format.
  */
@@ -14,2 +30,3 @@ export declare function createClientWithAutoPoll(apiKey: string, configCatKernel: IConfigCatKernel, options?: IAutoPollOptions): IConfigCatClient;
  * @param config - Configuration for manualPoll mode
+ * @deprecated This function is obsolete and will be removed from the public API in a future major version. To obtain a ConfigCatClient instance with manual polling for a specific SDK Key, please use the 'getClient(sdkKey, PollingMode.ManualPoll, options, ...)' format.
  */
@@ -21,2 +38,3 @@ export declare function createClientWithManualPoll(apiKey: string, configCatKernel: IConfigCatKernel, options?: IManualPollOptions): IConfigCatClient;
  * @param config - Configuration for lazyLoad mode
+ * @deprecated This function is obsolete and will be removed from the public API in a future major version. To obtain a ConfigCatClient instance with lazy loading for a specific SDK Key, please use the 'getClient(sdkKey, PollingMode.LazyLoad, options, ...)' format.
  */
@@ -26,68 +44,27 @@ export declare function createClientWithLazyLoad(apiKey: string, configCatKernel: IConfigCatKernel, options?: ILazyLoadingOptions): IConfigCatClient;
  * Create an instance of ConfigCatConsoleLogger
- * @param {LogLevel} logLevel - Specifies message's filtering to output for the CofigCatConsoleLogger.
+ * @param {LogLevel} logLevel - Specifies message's filtering to output for the ConfigCatConsoleLogger.
  */
 export declare function createConsoleLogger(logLevel: LogLevel): IConfigCatLogger;
-export interface IAutoPollOptions extends IOptions {
-    pollIntervalSeconds?: number;
-    maxInitWaitTimeSeconds?: number;
-    configChanged?: () => void;
-}
-export interface IManualPollOptions extends IOptions {
-}
-export interface ILazyLoadingOptions extends IOptions {
-    cacheTimeToLiveSeconds?: number;
-}
-export interface IConfigCatLogger {
-    debug(message: string): void;
-    /**
-     * @deprecated Use `debug(message: string)` method instead of this
-     */
-    log(message: string): void;
-    info(message: string): void;
-    warn(message: string): void;
-    error(message: string): void;
-}
-export declare enum LogLevel {
-    Debug = 4,
-    Info = 3,
-    Warn = 2,
-    Error = 1,
-    Off = -1
-}
-export interface IConfigCatKernel {
-    configFetcher: IConfigFetcher;
-    /**
-     * Default ICache implementation.
-     */
-    cache?: ICache;
-    sdkType: string;
-    sdkVersion: string;
-}
-export declare enum FetchStatus {
-    Fetched = 0,
-    NotModified = 1,
-    Errored = 2
-}
-export declare class FetchResult {
-    status: FetchStatus;
-    responseBody: string;
-    eTag?: string;
-    constructor(status: FetchStatus, responseBody: string, eTag?: string);
-    static success(responseBody: string, eTag: string): FetchResult;
-    static notModified(): FetchResult;
-    static error(): FetchResult;
-}
-export interface IConfigFetcher {
-    fetchLogic(options: OptionsBase, lastEtag: string | null, callback: (result: FetchResult) => void): void;
-}
-export interface ICache {
-    set(key: string, config: ProjectConfig): Promise<void> | void;
-    get(key: string): Promise<ProjectConfig | null> | ProjectConfig | null;
-}
-export { ProjectConfig } from "./ProjectConfig";
-export type { IConfigCatClient } from "./ConfigCatClient";
-export { OptionsBase, DataGovernance } from "./ConfigCatClientOptions";
+export type { IConfigCatKernel };
+export type { IConfigFetcher, IFetchResponse, FetchErrorCauses } from './ConfigFetcher';
+export { FetchStatus, FetchResult, FetchError } from './ConfigFetcher';
+export { OptionsBase } from "./ConfigCatClientOptions";
+export { InMemoryCache } from "./Cache";
+export type { IEventProvider, IEventEmitter } from "./EventEmitter";
+export { PollingMode };
+export type { IOptions } from "./ConfigCatClientOptions";
+export type { IAutoPollOptions, IManualPollOptions, ILazyLoadingOptions };
+export { DataGovernance } from "./ConfigCatClientOptions";
+export type { IConfigCatLogger };
+export { LogLevel };
+export type { ICache } from './Cache';
+export { ProjectConfig, RolloutRule, RolloutPercentageItem, Setting } from "./ProjectConfig";
+export type { IConfigCatClient };
+export { SettingKeyValue } from "./ConfigCatClient";
+export type { IEvaluationDetails, SettingTypeOf, SettingValue, VariationIdTypeOf, VariationIdValue } from "./RolloutEvaluator";
 export { User } from "./RolloutEvaluator";
 export type { IOverrideDataSource } from "./FlagOverrides";
 export { FlagOverrides, MapOverrideDataSource, OverrideBehaviour } from "./FlagOverrides";
+export { RefreshResult } from "./ConfigServiceBase";
+export type { IProvidesHooks, HookEvents } from "./Hooks";
 //# sourceMappingURL=index.d.ts.map

lib/index.js

 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.OverrideBehaviour = exports.MapOverrideDataSource = exports.FlagOverrides = exports.User = exports.DataGovernance = exports.OptionsBase = exports.ProjectConfig = exports.FetchResult = exports.FetchStatus = exports.LogLevel = exports.createConsoleLogger = exports.createClientWithLazyLoad = exports.createClientWithManualPoll = exports.createClientWithAutoPoll = void 0;
+exports.RefreshResult = exports.OverrideBehaviour = exports.MapOverrideDataSource = exports.FlagOverrides = exports.User = exports.SettingKeyValue = exports.Setting = exports.RolloutPercentageItem = exports.RolloutRule = exports.ProjectConfig = exports.LogLevel = exports.DataGovernance = exports.PollingMode = exports.InMemoryCache = exports.OptionsBase = exports.FetchError = exports.FetchResult = exports.FetchStatus = exports.createConsoleLogger = exports.createClientWithLazyLoad = exports.createClientWithManualPoll = exports.createClientWithAutoPoll = exports.disposeAllClients = exports.getClient = void 0;
 var ConfigCatClient_1 = require("./ConfigCatClient");
 var ConfigCatClientOptions_1 = require("./ConfigCatClientOptions");
+Object.defineProperty(exports, "PollingMode", { enumerable: true, get: function () { return ConfigCatClientOptions_1.PollingMode; } });
 var ConfigCatLogger_1 = require("./ConfigCatLogger");
+Object.defineProperty(exports, "LogLevel", { enumerable: true, get: function () { return ConfigCatLogger_1.LogLevel; } });
 var Polyfills_1 = require("./Polyfills");
 (0, Polyfills_1.setupPolyfills)();
 /**
+ * Returns an instance of ConfigCatClient for the specified SDK Key.
+ * @remarks This method returns a single, shared instance per each distinct SDK Key.
+ * That is, a new client object is created only when there is none available for the specified SDK Key.
+ * Otherwise, the already created instance is returned (in which case the 'pollingMode', 'options' and 'configCatKernel' arguments are ignored).
+ * So, please keep in mind that when you make multiple calls to this method using the same SDK Key, you may end up with multiple references to the same client object.
+ * @param sdkKey SDK Key (a.k.a ApiKey) to access configuration
+ * @param pollingMode The polling mode to use
+ * @param options Options for the specified polling mode
+ */
+function getClient(sdkKey, pollingMode, options, configCatKernel) {
+    return ConfigCatClient_1.ConfigCatClient.get(sdkKey, pollingMode, options, configCatKernel);
+}
+exports.getClient = getClient;
+/**
+ * Disposes all existing ConfigCatClient instances.
+ */
+function disposeAllClients() {
+    ConfigCatClient_1.ConfigCatClient.disposeAll();
+}
+exports.disposeAllClients = disposeAllClients;
+/**
  * Create an instance of ConfigCatClient and setup AutoPoll mode
  * @param {string} apiKey - ApiKey to access your configuration.
  * @param config - Configuration for autoPoll mode
+ * @deprecated This function is obsolete and will be removed from the public API in a future major version. To obtain a ConfigCatClient instance with auto polling for a specific SDK Key, please use the 'getClient(sdkKey, PollingMode.AutoPoll, options, ...)' format.
  */
 function createClientWithAutoPoll(apiKey, configCatKernel, options) {
-    return new ConfigCatClient_1.ConfigCatClient(new ConfigCatClientOptions_1.AutoPollOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache), configCatKernel);
+    return new ConfigCatClient_1.ConfigCatClient(new ConfigCatClientOptions_1.AutoPollOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache, configCatKernel.eventEmitterFactory), configCatKernel);
 }
@@ -22,5 +46,6 @@ exports.createClientWithAutoPoll = createClientWithAutoPoll;
  * @param config - Configuration for manualPoll mode
+ * @deprecated This function is obsolete and will be removed from the public API in a future major version. To obtain a ConfigCatClient instance with manual polling for a specific SDK Key, please use the 'getClient(sdkKey, PollingMode.ManualPoll, options, ...)' format.
  */
 function createClientWithManualPoll(apiKey, configCatKernel, options) {
-    return new ConfigCatClient_1.ConfigCatClient(new ConfigCatClientOptions_1.ManualPollOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache), configCatKernel);
+    return new ConfigCatClient_1.ConfigCatClient(new ConfigCatClientOptions_1.ManualPollOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache, configCatKernel.eventEmitterFactory), configCatKernel);
 }
@@ -32,5 +57,6 @@ exports.createClientWithManualPoll = createClientWithManualPoll;
  * @param config - Configuration for lazyLoad mode
+ * @deprecated This function is obsolete and will be removed from the public API in a future major version. To obtain a ConfigCatClient instance with lazy loading for a specific SDK Key, please use the 'getClient(sdkKey, PollingMode.LazyLoad, options, ...)' format.
  */
 function createClientWithLazyLoad(apiKey, configCatKernel, options) {
-    return new ConfigCatClient_1.ConfigCatClient(new ConfigCatClientOptions_1.LazyLoadOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache), configCatKernel);
+    return new ConfigCatClient_1.ConfigCatClient(new ConfigCatClientOptions_1.LazyLoadOptions(apiKey, configCatKernel.sdkType, configCatKernel.sdkVersion, options, configCatKernel.cache, configCatKernel.eventEmitterFactory), configCatKernel);
 }
@@ -40,3 +66,3 @@ exports.createClientWithLazyLoad = createClientWithLazyLoad;
  * Create an instance of ConfigCatConsoleLogger
- * @param {LogLevel} logLevel - Specifies message's filtering to output for the CofigCatConsoleLogger.
+ * @param {LogLevel} logLevel - Specifies message's filtering to output for the ConfigCatConsoleLogger.
  */
@@ -47,39 +73,19 @@ function createConsoleLogger(logLevel) {
 exports.createConsoleLogger = createConsoleLogger;
-var LogLevel;
-(function (LogLevel) {
-    LogLevel[LogLevel["Debug"] = 4] = "Debug";
-    LogLevel[LogLevel["Info"] = 3] = "Info";
-    LogLevel[LogLevel["Warn"] = 2] = "Warn";
-    LogLevel[LogLevel["Error"] = 1] = "Error";
-    LogLevel[LogLevel["Off"] = -1] = "Off";
-})(LogLevel = exports.LogLevel || (exports.LogLevel = {}));
-var FetchStatus;
-(function (FetchStatus) {
-    FetchStatus[FetchStatus["Fetched"] = 0] = "Fetched";
-    FetchStatus[FetchStatus["NotModified"] = 1] = "NotModified";
-    FetchStatus[FetchStatus["Errored"] = 2] = "Errored";
-})(FetchStatus = exports.FetchStatus || (exports.FetchStatus = {}));
-var FetchResult = /** @class */ (function () {
-    function FetchResult(status, responseBody, eTag) {
-        this.status = status;
-        this.responseBody = responseBody;
-        this.eTag = eTag;
-    }
-    FetchResult.success = function (responseBody, eTag) {
-        return new FetchResult(FetchStatus.Fetched, responseBody, eTag);
-    };
-    FetchResult.notModified = function () {
-        return new FetchResult(FetchStatus.NotModified, "");
-    };
-    FetchResult.error = function () {
-        return new FetchResult(FetchStatus.Errored, "");
-    };
-    return FetchResult;
-}());
-exports.FetchResult = FetchResult;
+var ConfigFetcher_1 = require("./ConfigFetcher");
+Object.defineProperty(exports, "FetchStatus", { enumerable: true, get: function () { return ConfigFetcher_1.FetchStatus; } });
+Object.defineProperty(exports, "FetchResult", { enumerable: true, get: function () { return ConfigFetcher_1.FetchResult; } });
+Object.defineProperty(exports, "FetchError", { enumerable: true, get: function () { return ConfigFetcher_1.FetchError; } });
+var ConfigCatClientOptions_2 = require("./ConfigCatClientOptions");
+Object.defineProperty(exports, "OptionsBase", { enumerable: true, get: function () { return ConfigCatClientOptions_2.OptionsBase; } });
+var Cache_1 = require("./Cache");
+Object.defineProperty(exports, "InMemoryCache", { enumerable: true, get: function () { return Cache_1.InMemoryCache; } });
+var ConfigCatClientOptions_3 = require("./ConfigCatClientOptions");
+Object.defineProperty(exports, "DataGovernance", { enumerable: true, get: function () { return ConfigCatClientOptions_3.DataGovernance; } });
 var ProjectConfig_1 = require("./ProjectConfig");
 Object.defineProperty(exports, "ProjectConfig", { enumerable: true, get: function () { return ProjectConfig_1.ProjectConfig; } });
-var ConfigCatClientOptions_2 = require("./ConfigCatClientOptions");
-Object.defineProperty(exports, "OptionsBase", { enumerable: true, get: function () { return ConfigCatClientOptions_2.OptionsBase; } });
-Object.defineProperty(exports, "DataGovernance", { enumerable: true, get: function () { return ConfigCatClientOptions_2.DataGovernance; } });
+Object.defineProperty(exports, "RolloutRule", { enumerable: true, get: function () { return ProjectConfig_1.RolloutRule; } });
+Object.defineProperty(exports, "RolloutPercentageItem", { enumerable: true, get: function () { return ProjectConfig_1.RolloutPercentageItem; } });
+Object.defineProperty(exports, "Setting", { enumerable: true, get: function () { return ProjectConfig_1.Setting; } });
+var ConfigCatClient_2 = require("./ConfigCatClient");
+Object.defineProperty(exports, "SettingKeyValue", { enumerable: true, get: function () { return ConfigCatClient_2.SettingKeyValue; } });
 var RolloutEvaluator_1 = require("./RolloutEvaluator");
@@ -91,1 +97,3 @@ Object.defineProperty(exports, "User", { enumerable: true, get: function () { return RolloutEvaluator_1.User; } });
 Object.defineProperty(exports, "OverrideBehaviour", { enumerable: true, get: function () { return FlagOverrides_1.OverrideBehaviour; } });
+var ConfigServiceBase_1 = require("./ConfigServiceBase");
+Object.defineProperty(exports, "RefreshResult", { enumerable: true, get: function () { return ConfigServiceBase_1.RefreshResult; } });

lib/LazyLoadConfigService.d.ts

@@ -1,11 +0,11 @@
-import { IConfigService, ConfigServiceBase } from "./ConfigServiceBase";
 import { LazyLoadOptions } from "./ConfigCatClientOptions";
-import { IConfigFetcher } from "./index";
+import type { IConfigFetcher } from "./ConfigFetcher";
+import { ConfigServiceBase, IConfigService, RefreshResult } from "./ConfigServiceBase";
 import { ProjectConfig } from "./ProjectConfig";
-export declare class LazyLoadConfigService extends ConfigServiceBase implements IConfigService {
+export declare class LazyLoadConfigService extends ConfigServiceBase<LazyLoadOptions> implements IConfigService {
     private cacheTimeToLiveSeconds;
-    constructor(configFetcher: IConfigFetcher, config: LazyLoadOptions);
+    constructor(configFetcher: IConfigFetcher, options: LazyLoadOptions);
     getConfig(): Promise<ProjectConfig | null>;
-    refreshConfigAsync(): Promise<ProjectConfig | null>;
+    refreshConfigAsync(): Promise<[RefreshResult, ProjectConfig | null]>;
 }
 //# sourceMappingURL=LazyLoadConfigService.d.ts.map

lib/LazyLoadConfigService.js

 "use strict";
-var __extends = (this && this.__extends) || (function () {
-    var extendStatics = function (d, b) {
-        extendStatics = Object.setPrototypeOf ||
-            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
-            function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
-        return extendStatics(d, b);
-    };
-    return function (d, b) {
-        if (typeof b !== "function" && b !== null)
-            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
-        extendStatics(d, b);
-        function __() { this.constructor = d; }
-        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
-    };
-})();
-var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
-    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
-    return new (P || (P = Promise))(function (resolve, reject) {
-        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
-        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
-        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
-        step((generator = generator.apply(thisArg, _arguments || [])).next());
-    });
-};
-var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
-    function verb(n) { return function (v) { return step([n, v]); }; }
-    function step(op) {
-        if (f) throw new TypeError("Generator is already executing.");
-        while (_) try {
-            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
-            if (y = 0, t) op = [op[0] & 2, t.value];
-            switch (op[0]) {
-                case 0: case 1: t = op; break;
-                case 4: _.label++; return { value: op[1], done: false };
-                case 5: _.label++; y = op[1]; op = [0]; continue;
-                case 7: op = _.ops.pop(); _.trys.pop(); continue;
-                default:
-                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
-                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
-                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
-                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
-                    if (t[2]) _.ops.pop();
-                    _.trys.pop(); continue;
-            }
-            op = body.call(thisArg, _);
-        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
-        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
-    }
-};
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.LazyLoadConfigService = void 0;
+var tslib_1 = require("tslib");
 var ConfigServiceBase_1 = require("./ConfigServiceBase");
+var ProjectConfig_1 = require("./ProjectConfig");
 var LazyLoadConfigService = /** @class */ (function (_super) {
-    __extends(LazyLoadConfigService, _super);
-    function LazyLoadConfigService(configFetcher, config) {
-        var _this = _super.call(this, configFetcher, config) || this;
-        _this.cacheTimeToLiveSeconds = config.cacheTimeToLiveSeconds;
+    tslib_1.__extends(LazyLoadConfigService, _super);
+    function LazyLoadConfigService(configFetcher, options) {
+        var _this = _super.call(this, configFetcher, options) || this;
+        _this.cacheTimeToLiveSeconds = options.cacheTimeToLiveSeconds;
+        options.hooks.emit("clientReady");
         return _this;
     }
     LazyLoadConfigService.prototype.getConfig = function () {
-        return __awaiter(this, void 0, void 0, function () {
-            var p;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            function logExpired(logger, appendix) {
+                if (appendix === void 0) { appendix = ""; }
+                logger.debug("LazyLoadConfigService.getConfig(): cache is empty or expired".concat(appendix, "."));
+            }
+            var config;
+            var _a;
+            return tslib_1.__generator(this, function (_b) {
+                switch (_b.label) {
                     case 0:
-                        this.baseConfig.logger.debug("LazyLoadConfigService.getConfig() called.");
-                        return [4 /*yield*/, this.baseConfig.cache.get(this.baseConfig.getCacheKey())];
+                        this.options.logger.debug("LazyLoadConfigService.getConfig() called.");
+                        return [4 /*yield*/, this.options.cache.get(this.options.getCacheKey())];
                     case 1:
-                        p = _a.sent();
-                        if (p && p.Timestamp + (this.cacheTimeToLiveSeconds * 1000) > new Date().getTime()) {
-                            this.baseConfig.logger.debug("LazyLoadConfigService.getConfig(): cache is valid, returning from cache.");
-                            return [2 /*return*/, p];
-                        }
-                        else {
-                            this.baseConfig.logger.debug("LazyLoadConfigService.getConfig(): cache is empty or expired, calling refreshLogicBaseAsync().");
-                            return [2 /*return*/, this.refreshLogicBaseAsync(p)];
-                        }
-                        return [2 /*return*/];
+                        config = _b.sent();
+                        if (!ProjectConfig_1.ProjectConfig.isExpired(config, this.cacheTimeToLiveSeconds * 1000)) return [3 /*break*/, 5];
+                        if (!!this.isOffline) return [3 /*break*/, 3];
+                        logExpired(this.options.logger, ", calling refreshConfigCoreAsync()");
+                        return [4 /*yield*/, this.refreshConfigCoreAsync(config)];
+                    case 2:
+                        _a = _b.sent(), config = _a[1];
+                        return [3 /*break*/, 4];
+                    case 3:
+                        logExpired(this.options.logger);
+                        _b.label = 4;
+                    case 4: return [2 /*return*/, config];
+                    case 5:
+                        this.options.logger.debug("LazyLoadConfigService.getConfig(): cache is valid, returning from cache.");
+                        return [2 /*return*/, config];
                 }
@@ -87,13 +49,6 @@ });
     LazyLoadConfigService.prototype.refreshConfigAsync = function () {
-        return __awaiter(this, void 0, void 0, function () {
-            var p;
-            return __generator(this, function (_a) {
-                switch (_a.label) {
-                    case 0:
-                        this.baseConfig.logger.debug("LazyLoadConfigService.refreshConfigAsync() called.");
-                        return [4 /*yield*/, this.baseConfig.cache.get(this.baseConfig.getCacheKey())];
-                    case 1:
-                        p = _a.sent();
-                        return [2 /*return*/, this.refreshLogicBaseAsync(p)];
-                }
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            return tslib_1.__generator(this, function (_a) {
+                this.options.logger.debug("LazyLoadConfigService.refreshConfigAsync() called.");
+                return [2 /*return*/, _super.prototype.refreshConfigAsync.call(this)];
             });
@@ -100,0 +55,0 @@ });

lib/Polyfills.d.ts

 export declare function setupPolyfills(): void;
+export declare function ObjectValuesPolyfill<T>(o: {
+    [s: string]: T;
+} | ArrayLike<T>): T[];
+export declare function ObjectEntriesPolyfill<T>(o: {
+    [s: string]: T;
+} | ArrayLike<T>): [string, T][];
+export declare function ObjectFromEntriesPolyfill<T>(entries: Iterable<readonly [PropertyKey, T]>): {
+    [k: PropertyKey]: T;
+};
+export declare function getWeakRefFallback<T extends object>(): WeakRefConstructor;
+export declare const isWeakRefAvailable: () => boolean;
 //# sourceMappingURL=Polyfills.d.ts.map

lib/Polyfills.js

 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.setupPolyfills = void 0;
+exports.isWeakRefAvailable = exports.getWeakRefFallback = exports.ObjectFromEntriesPolyfill = exports.ObjectEntriesPolyfill = exports.ObjectValuesPolyfill = exports.setupPolyfills = void 0;
 function setupPolyfills() {
-    if (!Object.fromEntries) {
-        Object.fromEntries = function (entries) {
-            if (!entries || !entries[Symbol.iterator]) {
-                throw new Error('Object.fromEntries() requires a single iterable argument');
-            }
-            var obj = {};
-            for (var _i = 0, entries_1 = entries; _i < entries_1.length; _i++) {
-                var _a = entries_1[_i], key = _a[0], value = _a[1];
-                obj[key] = value;
-            }
-            return obj;
-        };
+    // Object.values
+    if (typeof Object.values === "undefined") {
+        Object.values = ObjectValuesPolyfill;
     }
+    // Object.entries
+    if (typeof Object.entries === "undefined") {
+        Object.entries = ObjectEntriesPolyfill;
+    }
+    // Object.fromEntries
+    if (typeof Object.fromEntries === "undefined") {
+        Object.fromEntries = ObjectFromEntriesPolyfill;
+    }
+    // WeakRef
+    if (typeof WeakRef === "undefined") {
+        // There's no way to correctly polyfill WeakRef (https://stackoverflow.com/a/69971312/8656352),
+        // so we just polyfill its API (which means falling back on strong references in this case).
+        WeakRef = getWeakRefFallback();
+    }
 }
 exports.setupPolyfills = setupPolyfills;
+function ObjectValuesPolyfill(o) {
+    var result = [];
+    for (var _i = 0, _a = Object.keys(o); _i < _a.length; _i++) {
+        var key = _a[_i];
+        result.push(o[key]);
+    }
+    return result;
+}
+exports.ObjectValuesPolyfill = ObjectValuesPolyfill;
+function ObjectEntriesPolyfill(o) {
+    var result = [];
+    for (var _i = 0, _a = Object.keys(o); _i < _a.length; _i++) {
+        var key = _a[_i];
+        result.push([key, o[key]]);
+    }
+    return result;
+}
+exports.ObjectEntriesPolyfill = ObjectEntriesPolyfill;
+function ObjectFromEntriesPolyfill(entries) {
+    var _a;
+    var result = {};
+    if (Array.isArray(entries)) {
+        for (var _i = 0, entries_1 = entries; _i < entries_1.length; _i++) {
+            var _b = entries_1[_i], key = _b[0], value = _b[1];
+            result[key] = value;
+        }
+    }
+    else if (typeof Symbol !== "undefined" && (entries === null || entries === void 0 ? void 0 : entries[Symbol.iterator])) {
+        var iterator = entries[Symbol.iterator]();
+        var element = void 0, done = void 0;
+        while ((_a = iterator.next(), element = _a.value, done = _a.done, !done)) {
+            var key = element[0], value = element[1];
+            result[key] = value;
+        }
+    }
+    else {
+        throw new Error('Object.fromEntries() requires a single iterable argument');
+    }
+    return result;
+}
+exports.ObjectFromEntriesPolyfill = ObjectFromEntriesPolyfill;
+function getWeakRefFallback() {
+    var WeakRef = function (target) {
+        this.target = target;
+    };
+    WeakRef.prototype.deref = function () {
+        return this.target;
+    };
+    WeakRef.isFallback = true;
+    return WeakRef;
+}
+exports.getWeakRefFallback = getWeakRefFallback;
+var isWeakRefAvailable = function () { return typeof WeakRef === "function" && !WeakRef.hasOwnProperty("isFallback"); };
+exports.isWeakRefAvailable = isWeakRefAvailable;

lib/ProjectConfig.d.ts

@@ -6,5 +6,5 @@ export declare class ProjectConfig {
     ConfigJSON: any;
-    /** Timestamp in milliseconds */
+    /** Timestamp of last successful download (regardless of whether the config has changed or not) in milliseconds */
     Timestamp: number;
-    constructor(timeStamp: number, jsonConfig: string, httpETag?: string);
+    constructor(timeStamp: number, jsonConfig: string | object, httpETag?: string);
     /**
@@ -16,2 +16,3 @@ * Determines whether the specified ProjectConfig instances are considered equal.
     private static ensureStrictEtag;
+    static isExpired(projectConfig: ProjectConfig | null, expirationMs: number): boolean;
 }
@@ -18,0 +19,0 @@ export declare class ConfigFile {

lib/ProjectConfig.js

 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.RolloutPercentageItem = exports.RolloutRule = exports.Setting = exports.Preferences = exports.ConfigFile = exports.ProjectConfig = void 0;
+// NOTE: No instance methods should be added to this class!
+// Flawed ICache implementations may erase the prototype information (when serialization is involved),
+// which would lead to "... is not a function" errors in the case of instance methods.
+// (As a matter of fact, this type should have been defined as an interface to prevent such complications but
+// we can't really change this any more because this would be a too dangerous breaking change at this point.)
 var ProjectConfig = /** @class */ (function () {
     function ProjectConfig(timeStamp, jsonConfig, httpETag) {
         this.Timestamp = timeStamp;
-        this.ConfigJSON = JSON.parse(jsonConfig);
+        this.ConfigJSON = typeof jsonConfig === "string" ? JSON.parse(jsonConfig) : jsonConfig;
         this.HttpETag = httpETag;
@@ -14,5 +19,14 @@ }
     ProjectConfig.equals = function (projectConfig1, projectConfig2) {
-        if (!projectConfig1 || !projectConfig2)
+        if (!projectConfig1) {
+            // If both configs are null, we consider them equal.
+            return !projectConfig2;
+        }
+        if (!projectConfig2) {
             return false;
-        return this.compareEtags(projectConfig1.HttpETag, projectConfig2.HttpETag);
+        }
+        // When both ETags are available, we don't need to check the JSON content
+        // (because of how HTTP ETags work - see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag).
+        return !!projectConfig1.HttpETag && !!projectConfig2.HttpETag
+            ? this.compareEtags(projectConfig1.HttpETag, projectConfig2.HttpETag)
+            : JSON.stringify(projectConfig1.ConfigJSON) === JSON.stringify(projectConfig2.ConfigJSON);
     };
@@ -31,2 +45,5 @@ ProjectConfig.compareEtags = function (etag1, etag2) {
     };
+    ProjectConfig.isExpired = function (projectConfig, expirationMs) {
+        return !projectConfig || projectConfig.Timestamp + expirationMs < new Date().getTime();
+    };
     return ProjectConfig;
@@ -33,0 +50,0 @@ }());

lib/RolloutEvaluator.d.ts

@@ -1,8 +0,32 @@
-import { IConfigCatLogger } from "./index";
-import { Setting } from "./ProjectConfig";
+import { LoggerWrapper } from "./ConfigCatLogger";
+import { ProjectConfig, RolloutPercentageItem, RolloutRule, Setting } from "./ProjectConfig";
+export type SettingValue = boolean | number | string | null | undefined;
+export type SettingTypeOf<T> = T extends boolean ? boolean : T extends number ? number : T extends string ? string : T extends null ? boolean | number | string | null : T extends undefined ? boolean | number | string | undefined : any;
+export type VariationIdValue = string | null | undefined;
+export type VariationIdTypeOf<T> = T extends string ? string : T extends null ? string | null : T extends undefined ? string | undefined : any;
 export interface IRolloutEvaluator {
-    Evaluate(settings: {
-        [name: string]: Setting;
-    }, key: string, defaultValue: any, user?: User, defaultVariationId?: any): ValueAndVariationId;
+    Evaluate(setting: Setting, key: string, defaultValue: SettingValue, user: User | undefined, remoteConfig: ProjectConfig | null, defaultVariationId?: VariationIdValue): IEvaluationDetails;
 }
+export interface IEvaluationDetails<TValue = SettingValue> {
+    /** Key of the feature or setting flag. */
+    key: string;
+    /** Evaluated value of the feature or setting flag. */
+    value: TValue;
+    /** Variation ID of the feature or setting flag (if available). */
+    variationId?: VariationIdValue;
+    /** Time of last successful download of config.json (if there has been a successful download already). */
+    fetchTime?: Date;
+    /** The User object used for the evaluation (if available). */
+    user?: User;
+    /** Indicates whether the default value passed to IConfigCatClient.getValue or IConfigCatClient.getValueAsync is used as the result of the evaluation. */
+    isDefaultValue: boolean;
+    /** Error message in case evaluation failed. */
+    errorMessage?: string;
+    /** The exception object related to the error in case evaluation failed (if any). */
+    errorException?: any;
+    /** The comparison-based targeting rule which was used to select the evaluated value (if any). */
+    matchedEvaluationRule?: RolloutRule;
+    /** The percentage-based targeting rule which was used to select the evaluated value (if any). */
+    matchedEvaluationPercentageRule?: RolloutPercentageItem;
+}
 /** Object for variation evaluation */
@@ -26,8 +50,6 @@ export declare class User {
     private logger;
-    constructor(logger: IConfigCatLogger);
-    Evaluate(settings: {
-        [name: string]: Setting;
-    }, key: string, defaultValue: any, user?: User, defaultVariationId?: any): ValueAndVariationId;
+    constructor(logger: LoggerWrapper);
+    Evaluate(setting: Setting, key: string, defaultValue: SettingValue, user: User | undefined, remoteConfig: ProjectConfig | null): IEvaluationDetails;
     private EvaluateRules;
-    private EvaluateVariations;
+    private EvaluatePercentageRules;
     private EvaluateNumber;
@@ -38,7 +60,22 @@ private EvaluateSemver;
 }
-declare class ValueAndVariationId {
-    Value: any;
-    VariationId: any;
-}
-export {};
+export declare function evaluationDetailsFromDefaultValue<T extends SettingValue>(key: string, defaultValue: T, fetchTime?: Date, user?: User, errorMessage?: string, errorException?: any): IEvaluationDetails<SettingTypeOf<T>>;
+export declare function evaluationDetailsFromDefaultVariationId(key: string, defaultVariationId: VariationIdValue, fetchTime?: Date, user?: User, errorMessage?: string, errorException?: any): IEvaluationDetails;
+export declare function evaluate<T extends SettingValue>(evaluator: IRolloutEvaluator, settings: {
+    [name: string]: Setting;
+} | null, key: string, defaultValue: T, user: User | undefined, remoteConfig: ProjectConfig | null, logger: LoggerWrapper): IEvaluationDetails<SettingTypeOf<T>>;
+export declare function evaluateVariationId(evaluator: IRolloutEvaluator, settings: {
+    [name: string]: Setting;
+} | null, key: string, defaultVariationId: VariationIdValue, user: User | undefined, remoteConfig: ProjectConfig | null, logger: LoggerWrapper): IEvaluationDetails;
+export declare function evaluateAll(evaluator: IRolloutEvaluator, settings: {
+    [name: string]: Setting;
+} | null, user: User | undefined, remoteConfig: ProjectConfig | null, logger: LoggerWrapper): [IEvaluationDetails[], any[] | undefined];
+export declare function evaluateAllVariationIds(evaluator: IRolloutEvaluator, settings: {
+    [name: string]: Setting;
+} | null, user: User | undefined, remoteConfig: ProjectConfig | null, logger: LoggerWrapper): [IEvaluationDetails[], any[] | undefined];
+export declare function checkSettingsAvailable(settings: {
+    [name: string]: Setting;
+} | null, logger: LoggerWrapper, appendix?: string): settings is {
+    [name: string]: Setting;
+};
+export declare function ensureAllowedDefaultValue(value: SettingValue): void;
 //# sourceMappingURL=RolloutEvaluator.d.ts.map

lib/RolloutEvaluator.js

 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.RolloutEvaluator = exports.User = void 0;
+exports.ensureAllowedDefaultValue = exports.checkSettingsAvailable = exports.evaluateAllVariationIds = exports.evaluateAll = exports.evaluateVariationId = exports.evaluate = exports.evaluationDetailsFromDefaultVariationId = exports.evaluationDetailsFromDefaultValue = exports.RolloutEvaluator = exports.User = void 0;
+var ProjectConfig_1 = require("./ProjectConfig");
+var semver = require("./Semver");
 var Sha1_1 = require("./Sha1");
-var semver = require("./Semver");
 var Utils_1 = require("./Utils");
@@ -24,11 +25,4 @@ /** Object for variation evaluation */
     }
-    RolloutEvaluator.prototype.Evaluate = function (settings, key, defaultValue, user, defaultVariationId) {
+    RolloutEvaluator.prototype.Evaluate = function (setting, key, defaultValue, user, remoteConfig) {
         this.logger.debug("RolloutEvaluator.Evaluate() called.");
-        if (!settings[key]) {
-            var s = "Evaluating getValue('" + key + "') failed. Returning default value: '" + defaultValue + "'.";
-            s += " Here are the available keys: {" + Object.keys(settings).join() + "}.";
-            this.logger.error(s);
-            return { Value: defaultValue, VariationId: defaultVariationId };
-        }
-        var featureFlag = settings[key];
         var eLog = new EvaluateLogger();
@@ -38,39 +32,44 @@ eLog.User = user;
         eLog.ReturnValue = defaultValue;
-        var result = new EvaluateResult();
-        result.EvaluateLog = eLog;
-        if (user) {
-            result = this.EvaluateRules(featureFlag.rolloutRules, user, eLog);
-            if (result.ValueAndVariationId == null) {
-                result.ValueAndVariationId = this.EvaluateVariations(featureFlag.rolloutPercentageItems, key, user);
-                if (result.ValueAndVariationId) {
-                    result.EvaluateLog.ReturnValue = result.ValueAndVariationId.Value;
+        var result;
+        try {
+            if (user) {
+                // evaluate comparison-based rules
+                result = this.EvaluateRules(setting.rolloutRules, user, eLog);
+                if (result !== null) {
+                    eLog.ReturnValue = result.value;
+                    return evaluationDetailsFromEvaluateResult(key, result, (0, Utils_1.getTimestampAsDate)(remoteConfig), user);
                 }
-                if (featureFlag.rolloutPercentageItems.length > 0) {
-                    result.EvaluateLog.OpAppendLine("Evaluating % options => " + (result.ValueAndVariationId == null ? "user not targeted" : "user targeted"));
+                // evaluate percentage-based rules
+                result = this.EvaluatePercentageRules(setting.rolloutPercentageItems, key, user);
+                if (setting.rolloutPercentageItems && setting.rolloutPercentageItems.length > 0) {
+                    eLog.OpAppendLine("Evaluating % options => " + (!result ? "user not targeted" : "user targeted"));
                 }
+                if (result !== null) {
+                    eLog.ReturnValue = result.value;
+                    return evaluationDetailsFromEvaluateResult(key, result, (0, Utils_1.getTimestampAsDate)(remoteConfig), user);
+                }
             }
-        }
-        else {
-            if ((featureFlag.rolloutRules && featureFlag.rolloutRules.length > 0) ||
-                (featureFlag.rolloutPercentageItems && featureFlag.rolloutPercentageItems.length > 0)) {
-                var s = "Evaluating getValue('" + key + "'). ";
-                s += "UserObject missing! You should pass a UserObject to getValue(), in order to make targeting work properly. ";
-                s += "Read more: https://configcat.com/docs/advanced/user-object";
-                this.logger.warn(s);
+            else {
+                if ((setting.rolloutRules && setting.rolloutRules.length > 0) ||
+                    (setting.rolloutPercentageItems && setting.rolloutPercentageItems.length > 0)) {
+                    var s = "Evaluating getValue('" + key + "'). ";
+                    s += "UserObject missing! You should pass a UserObject to getValue(), in order to make targeting work properly. ";
+                    s += "Read more: https://configcat.com/docs/advanced/user-object";
+                    this.logger.warn(s);
+                }
             }
-        }
-        if (result.ValueAndVariationId == null) {
-            result.ValueAndVariationId = {
-                Value: featureFlag.value,
-                VariationId: featureFlag.variationId,
+            // regular evaluate
+            result = {
+                value: setting.value,
+                variationId: setting.variationId
             };
-            result.EvaluateLog.ReturnValue = result.ValueAndVariationId.Value;
+            eLog.ReturnValue = result.value;
+            return evaluationDetailsFromEvaluateResult(key, result, (0, Utils_1.getTimestampAsDate)(remoteConfig), user);
         }
-        this.logger.info(result.EvaluateLog.GetLog());
-        return result.ValueAndVariationId;
+        finally {
+            this.logger.info(eLog.GetLog());
+        }
     };
     RolloutEvaluator.prototype.EvaluateRules = function (rolloutRules, user, eLog) {
         this.logger.debug("RolloutEvaluator.EvaluateRules() called.");
-        var result = new EvaluateResult();
-        result.ValueAndVariationId = null;
         if (rolloutRules && rolloutRules.length > 0) {
@@ -88,2 +87,7 @@ var _loop_1 = function (i) {
                 }
+                var result = {
+                    value: rule.value,
+                    variationId: rule.variationId,
+                    matchedRule: rule
+                };
                 switch (comparator) {
@@ -96,8 +100,2 @@ case 0: // is one of
                                 eLog.OpAppendLine(log);
-                                result.ValueAndVariationId = {
-                                    Value: rule.value,
-                                    VariationId: rule.variationId
-                                };
-                                eLog.ReturnValue = result.ValueAndVariationId.Value;
-                                result.EvaluateLog = eLog;
                                 return { value: result };
@@ -117,8 +115,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -132,8 +124,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -147,8 +133,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -167,8 +147,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -187,8 +161,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -204,8 +172,2 @@ }
                                 eLog.OpAppendLine(log);
-                                result.ValueAndVariationId = {
-                                    Value: rule.value,
-                                    VariationId: rule.variationId
-                                };
-                                eLog.ReturnValue = result.ValueAndVariationId.Value;
-                                result.EvaluateLog = eLog;
                                 return { value: result };
@@ -225,8 +187,2 @@ }
                             eLog.OpAppendLine(log);
-                            result.ValueAndVariationId = {
-                                Value: rule.value,
-                                VariationId: rule.variationId
-                            };
-                            eLog.ReturnValue = result.ValueAndVariationId.Value;
-                            result.EvaluateLog = eLog;
                             return { value: result };
@@ -248,9 +204,8 @@ }
         }
-        result.EvaluateLog = eLog;
-        return result;
+        return null;
     };
-    RolloutEvaluator.prototype.EvaluateVariations = function (rolloutPercentageItems, key, user) {
+    RolloutEvaluator.prototype.EvaluatePercentageRules = function (rolloutPercentageItems, key, user) {
         this.logger.debug("RolloutEvaluator.EvaluateVariations() called.");
         if (rolloutPercentageItems && rolloutPercentageItems.length > 0) {
-            var hashCandidate = key + ((user.identifier === null || user.identifier === undefined) ? '' : user.identifier);
+            var hashCandidate = key + ((user.identifier === null || user.identifier === void 0) ? '' : user.identifier);
             var hashValue = (0, Sha1_1.sha1)(hashCandidate).substring(0, 7);
@@ -260,8 +215,9 @@ var hashScale = parseInt(hashValue, 16) % 100;
             for (var i = 0; i < rolloutPercentageItems.length; i++) {
-                var variation = rolloutPercentageItems[i];
-                bucket += +variation.percentage;
+                var percentageRule = rolloutPercentageItems[i];
+                bucket += +percentageRule.percentage;
                 if (hashScale < bucket) {
                     return {
-                        Value: variation.value,
-                        VariationId: variation.variationId
+                        value: percentageRule.value,
+                        variationId: percentageRule.variationId,
+                        matchedRule: percentageRule
                     };
@@ -423,12 +379,2 @@ }
 exports.RolloutEvaluator = RolloutEvaluator;
-var ValueAndVariationId = /** @class */ (function () {
-    function ValueAndVariationId() {
-    }
-    return ValueAndVariationId;
-}());
-var EvaluateResult = /** @class */ (function () {
-    function EvaluateResult() {
-    }
-    return EvaluateResult;
-}());
 var EvaluateLogger = /** @class */ (function () {
@@ -449,1 +395,129 @@ function EvaluateLogger() {
 }());
+/* Helper functions */
+function evaluationDetailsFromEvaluateResult(key, evaluateResult, fetchTime, user) {
+    return {
+        key: key,
+        value: evaluateResult.value,
+        variationId: evaluateResult.variationId,
+        fetchTime: fetchTime,
+        user: user,
+        isDefaultValue: false,
+        matchedEvaluationRule: evaluateResult.matchedRule instanceof ProjectConfig_1.RolloutRule ? evaluateResult.matchedRule : void 0,
+        matchedEvaluationPercentageRule: evaluateResult.matchedRule instanceof ProjectConfig_1.RolloutPercentageItem ? evaluateResult.matchedRule : void 0,
+    };
+}
+function evaluationDetailsFromDefaultValue(key, defaultValue, fetchTime, user, errorMessage, errorException) {
+    return {
+        key: key,
+        value: defaultValue,
+        fetchTime: fetchTime,
+        user: user,
+        isDefaultValue: true,
+        errorMessage: errorMessage,
+        errorException: errorException
+    };
+}
+exports.evaluationDetailsFromDefaultValue = evaluationDetailsFromDefaultValue;
+function evaluationDetailsFromDefaultVariationId(key, defaultVariationId, fetchTime, user, errorMessage, errorException) {
+    return {
+        key: key,
+        value: null,
+        variationId: defaultVariationId,
+        fetchTime: fetchTime,
+        user: user,
+        isDefaultValue: true,
+        errorMessage: errorMessage,
+        errorException: errorException
+    };
+}
+exports.evaluationDetailsFromDefaultVariationId = evaluationDetailsFromDefaultVariationId;
+function evaluate(evaluator, settings, key, defaultValue, user, remoteConfig, logger) {
+    var errorMessage;
+    if (!settings) {
+        errorMessage = "config.json is not present. Returning default value: '".concat(defaultValue, "'.");
+        logger.error(errorMessage);
+        return evaluationDetailsFromDefaultValue(key, defaultValue, (0, Utils_1.getTimestampAsDate)(remoteConfig), user, errorMessage);
+    }
+    var setting = settings[key];
+    if (!setting) {
+        errorMessage = "Evaluating '".concat(key, "' failed (key was not found in config.json). Returning default value: '").concat(defaultValue, "'. These are the available keys: ").concat(keysToString(settings), ".");
+        logger.error(errorMessage);
+        return evaluationDetailsFromDefaultValue(key, defaultValue, (0, Utils_1.getTimestampAsDate)(remoteConfig), user, errorMessage);
+    }
+    ensureAllowedDefaultValue(defaultValue);
+    var evaluationDetails = evaluator.Evaluate(setting, key, defaultValue, user, remoteConfig);
+    if (defaultValue !== null && defaultValue !== void 0 && typeof defaultValue !== typeof evaluationDetails.value) {
+        throw new Error("The type of a setting must match the type of the given default value.\nThe setting's type was ".concat(typeof defaultValue, ", the given default value's type was ").concat(typeof evaluationDetails.value, ".\nPlease pass a corresponding default value type."));
+    }
+    return evaluationDetails;
+}
+exports.evaluate = evaluate;
+function evaluateVariationId(evaluator, settings, key, defaultVariationId, user, remoteConfig, logger) {
+    var errorMessage;
+    if (!settings) {
+        errorMessage = "config.json is not present. Returning default variationId: '".concat(defaultVariationId, "'.");
+        logger.error(errorMessage);
+        return evaluationDetailsFromDefaultVariationId(key, defaultVariationId, (0, Utils_1.getTimestampAsDate)(remoteConfig), user, errorMessage);
+    }
+    var setting = settings[key];
+    if (!setting) {
+        errorMessage = "Evaluating '".concat(key, "' failed (key was not found in config.json). Returning default variationId: '").concat(defaultVariationId, "'. These are the available keys: ").concat(keysToString(settings), ".");
+        logger.error(errorMessage);
+        return evaluationDetailsFromDefaultVariationId(key, defaultVariationId, (0, Utils_1.getTimestampAsDate)(remoteConfig), user, errorMessage);
+    }
+    return evaluator.Evaluate(setting, key, null, user, remoteConfig, defaultVariationId);
+}
+exports.evaluateVariationId = evaluateVariationId;
+function evaluateAllCore(evaluator, settings, user, remoteConfig, logger, getDetailsForError) {
+    var errors;
+    if (!checkSettingsAvailable(settings, logger, ", returning empty array")) {
+        return [[], errors];
+    }
+    var evaluationDetailsArray = [];
+    var index = 0;
+    for (var _i = 0, _a = Object.entries(settings); _i < _a.length; _i++) {
+        var _b = _a[_i], key = _b[0], setting = _b[1];
+        var evaluationDetails = void 0;
+        try {
+            evaluationDetails = evaluator.Evaluate(setting, key, null, user, remoteConfig);
+        }
+        catch (err) {
+            errors !== null && errors !== void 0 ? errors : (errors = []);
+            errors.push(err);
+            evaluationDetails = getDetailsForError(key, (0, Utils_1.getTimestampAsDate)(remoteConfig), user, err);
+        }
+        evaluationDetailsArray[index++] = evaluationDetails;
+    }
+    return [evaluationDetailsArray, errors];
+}
+function evaluateAll(evaluator, settings, user, remoteConfig, logger) {
+    return evaluateAllCore(evaluator, settings, user, remoteConfig, logger, function (key, fetchTime, user, err) { return evaluationDetailsFromDefaultValue(key, null, fetchTime, user, (0, Utils_1.errorToString)(err), err); });
+}
+exports.evaluateAll = evaluateAll;
+function evaluateAllVariationIds(evaluator, settings, user, remoteConfig, logger) {
+    return evaluateAllCore(evaluator, settings, user, remoteConfig, logger, function (key, fetchTime, user, err) { return evaluationDetailsFromDefaultVariationId(key, null, fetchTime, user, (0, Utils_1.errorToString)(err), err); });
+}
+exports.evaluateAllVariationIds = evaluateAllVariationIds;
+function checkSettingsAvailable(settings, logger, appendix) {
+    if (appendix === void 0) { appendix = ""; }
+    if (!settings) {
+        logger.error("config.json is not present".concat(appendix));
+        return false;
+    }
+    return true;
+}
+exports.checkSettingsAvailable = checkSettingsAvailable;
+function ensureAllowedDefaultValue(value) {
+    if (value === null || value === void 0) {
+        return;
+    }
+    var type = typeof value;
+    if (type === "boolean" || type === "number" || type === "string") {
+        return;
+    }
+    throw new Error("The default value must be boolean, number, string, null or undefined.");
+}
+exports.ensureAllowedDefaultValue = ensureAllowedDefaultValue;
+function keysToString(settings) {
+    return Object.keys(settings).join();
+}

lib/Semver.js

@@ -33,3 +33,3 @@ "use strict";
     src[index] = value;
-    re[index] = new RegExp(value, undefined);
+    re[index] = new RegExp(value);
 };
@@ -167,9 +167,9 @@ createToken('NUMERICIDENTIFIER', '0|[1-9]\\d*');
             var b = other.prerelease[i];
-            if (a === undefined && b === undefined) {
+            if (a === void 0 && b === void 0) {
                 return 0;
             }
-            else if (b === undefined) {
+            else if (b === void 0) {
                 return 1;
             }
-            else if (a === undefined) {
+            else if (a === void 0) {
                 return -1;
@@ -193,9 +193,9 @@ }
             var b = other.build[i];
-            if (a === undefined && b === undefined) {
+            if (a === void 0 && b === void 0) {
                 return 0;
             }
-            else if (b === undefined) {
+            else if (b === void 0) {
                 return 1;
             }
-            else if (a === undefined) {
+            else if (a === void 0) {
                 return -1;
@@ -202,0 +202,0 @@ }

lib/Utils.d.ts

@@ -1,6 +0,9 @@
-import { Setting } from "./ProjectConfig";
+import { ProjectConfig, Setting } from "./ProjectConfig";
 export declare const isUndefined: (comp: any) => boolean;
+export declare function delay(delayMs: number, obtainCancel?: (cancel: () => void) => void): Promise<void>;
 export declare function getSettingsFromConfig(json: any): {
     [name: string]: Setting;
 };
+export declare function getTimestampAsDate(projectConfig: ProjectConfig | null): Date | undefined;
+export declare function errorToString(err: any, includeStackTrace?: boolean): string;
 //# sourceMappingURL=Utils.d.ts.map

lib/Utils.js

 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.getSettingsFromConfig = exports.isUndefined = void 0;
+exports.errorToString = exports.getTimestampAsDate = exports.getSettingsFromConfig = exports.delay = exports.isUndefined = void 0;
 var ProjectConfig_1 = require("./ProjectConfig");
-var isUndefined = function (comp) { return comp === undefined; };
+var isUndefined = function (comp) { return comp === void 0; };
 exports.isUndefined = isUndefined;
+function delay(delayMs, obtainCancel) {
+    var timerId;
+    var promise = new Promise(function (resolve) { return timerId = setTimeout(resolve, delayMs); });
+    obtainCancel === null || obtainCancel === void 0 ? void 0 : obtainCancel(function () { return clearTimeout(timerId); });
+    return promise;
+}
+exports.delay = delay;
+;
 function getSettingsFromConfig(json) {
-    if (!json) {
-        return {};
-    }
     return Object.fromEntries(Object.entries(json[ProjectConfig_1.ConfigFile.FeatureFlags]).map(function (_a) {
@@ -17,1 +22,12 @@ var key = _a[0], value = _a[1];
 exports.getSettingsFromConfig = getSettingsFromConfig;
+function getTimestampAsDate(projectConfig) {
+    return projectConfig ? new Date(projectConfig.Timestamp) : void 0;
+}
+exports.getTimestampAsDate = getTimestampAsDate;
+function errorToString(err, includeStackTrace) {
+    if (includeStackTrace === void 0) { includeStackTrace = false; }
+    return err instanceof Error
+        ? includeStackTrace && err.stack ? err.stack : err.toString()
+        : err + "";
+}
+exports.errorToString = errorToString;

package.json

 {
   "name": "configcat-common",
-  "version": "6.0.1",
+  "version": "7.0.0",
   "description": "ConfigCat is a configuration as a service that lets you manage your features and configurations without actually deploying new code.",
@@ -10,6 +10,6 @@ "main": "lib/index.js",
     "coverage": "nyc npm run test",
-    "build": "tsc -p tsconfig.cjs.json && tsc -p tsconfig.esm.json && tsc -p tsconfig.legacy.json",
+    "build": "tsc -p tsconfig.build.cjs.json && tsc -p tsconfig.build.esm.json",
     "prepare": "npm run build",
-    "test": "mocha --require ts-node/register test/**/*.ts --exit --timeout 30000",
-    "test-debug": "mocha --fgrep \"TITLE_OF_TEST\" --require ts-node/register test/**/*.ts --exit --timeout 30000"
+    "test": "cross-env TS_NODE_PROJECT=./tsconfig.mocha.json node --expose-gc node_modules/mocha/bin/_mocha --require ts-node/register 'test/**/*.ts' --exit --timeout 30000",
+    "test-debug": "cross-env TS_NODE_PROJECT=./tsconfig.mocha.json node --expose-gc node_modules/mocha/bin/_mocha --fgrep \"TITLE_OF_TEST\" --require ts-node/register 'test/**/*.ts' --exit --timeout 30000"
   },
@@ -32,8 +32,12 @@ "keywords": [
   "homepage": "https://configcat.com",
+  "dependencies": {
+    "tslib": "^2.4.1"
+  },
   "devDependencies": {
-    "@types/chai": "4.3.3",
-    "@types/mocha": "^9.1.1",
-    "@types/node": "^17.0.45",
-    "chai": "^4.3.6",
-    "mocha": "^10.0.0",
+    "@types/chai": "4.3.4",
+    "@types/mocha": "^10.0.1",
+    "@types/node": "^18.11.18",
+    "chai": "^4.3.7",
+    "cross-env": "^7.0.3",
+    "mocha": "^10.2.0",
     "moq.ts": "^7.4.1",
@@ -43,3 +47,3 @@ "nyc": "^15.1.0",
     "ts-node": "^10.9.1",
-    "typescript": "^4.7.4"
+    "typescript": "^4.9.4"
   },
@@ -46,0 +50,0 @@ "repository": {

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Found 1 instance in 1 package

Major refactor

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Package has recently undergone a major refactor. It may be unstable or indicate significant internal changes. Use caution when updating to versions that include significant changes.

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Fixed alerts

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Worsened metrics

Total package byte prevSize

382687

decreased by-14.65%

Dependency count

1

increased byInfinity%

Dev dependency count

11

increased by10%

Number of package files

86

decreased by-42.28%

Lines of code

7205

decreased by-14.33%

Dependency changes

• + Addedtslib@^2.4.1

• + Addedtslib@2.7.0(transitive)