@open-draft/deferred-promise - npm Package Compare versions

Comparing version 2.0.0 to 2.1.0

build/createDeferredExecutor.d.ts

 export declare type PromiseState = 'pending' | 'fulfilled' | 'rejected';
-export declare type ResolveFunction<Data extends any, Result = void> = (value: Data) => Result | PromiseLike<Result>;
-export declare type RejectFunction<Result = unknown> = (reason?: unknown) => Result | PromiseLike<Result>;
-export declare type DeferredPromiseExecutor<Input = void, Output = Input> = {
-    (resolve?: ResolveFunction<any, unknown>, reject?: RejectFunction): void;
-    resolve: ResolveFunction<Input, Output | void>;
-    reject: RejectFunction;
-    result?: Output | Input;
+export declare type Executor<Value> = ConstructorParameters<typeof Promise<Value>>[0];
+export declare type ResolveFunction<Value> = Parameters<Executor<Value>>[0];
+export declare type RejectFunction<Reason> = Parameters<Executor<Reason>>[1];
+export declare type DeferredPromiseExecutor<Input = never, Output = Input> = {
+    (resolve?: ResolveFunction<Input>, reject?: RejectFunction<any>): void;
+    resolve: ResolveFunction<Input>;
+    reject: RejectFunction<any>;
+    result?: Output;
     state: PromiseState;
@@ -10,0 +11,0 @@ rejectionReason?: unknown;

build/createDeferredExecutor.js

@@ -8,18 +8,20 @@ "use strict";
         executor.resolve = (data) => {
-            queueMicrotask(() => {
-                if (executor.state === 'pending') {
-                    executor.state = 'fulfilled';
-                    executor.result = data;
-                    resolve(data);
-                }
-            });
+            if (executor.state !== 'pending') {
+                return;
+            }
+            executor.result = data;
+            const onFulfilled = (value) => {
+                executor.state = 'fulfilled';
+                return value;
+            };
+            return resolve(data instanceof Promise ? data : Promise.resolve(data).then(onFulfilled));
         };
         executor.reject = (reason) => {
+            if (executor.state !== 'pending') {
+                return;
+            }
             queueMicrotask(() => {
-                if (executor.state === 'pending') {
-                    executor.state = 'rejected';
-                    executor.rejectionReason = reason;
-                    reject(reason);
-                }
+                executor.state = 'rejected';
             });
+            return reject((executor.rejectionReason = reason));
         };
@@ -26,0 +28,0 @@ });

build/DeferredPromise.d.ts

@@ -1,23 +0,12 @@
-import { PromiseState, ResolveFunction, RejectFunction } from './createDeferredExecutor';
-/**
- * @example
- * function getPort() {
- *   const portReadyPromise = new DeferredPromise<number>()
- *   port.on('ready', (port) => portReadyPromise.resolve(port))
- *   port.on('error', (error) => portReadyPromise.reject(error))
- *   returtn portReadyPromise
- * }
- */
-export declare class DeferredPromise<Input = never, Output = Input> {
+import { type Executor, type RejectFunction, type ResolveFunction } from './createDeferredExecutor';
+export declare class DeferredPromise<Input, Output = Input> extends Promise<Input> {
     #private;
-    resolve: (value: Input) => void;
-    reject: (reason?: unknown) => void;
-    constructor();
-    static get [Symbol.species](): PromiseConstructor;
-    get [Symbol.toStringTag](): string;
-    get state(): PromiseState;
+    resolve: ResolveFunction<Output>;
+    reject: RejectFunction<Output>;
+    constructor(executor?: Executor<Input> | null);
+    get state(): import("./createDeferredExecutor").PromiseState;
     get rejectionReason(): unknown;
-    then<FulfillmentResult = Output, RejectionResult = never>(onFulfilled?: ResolveFunction<Output, FulfillmentResult> | null, onRejected?: RejectFunction<RejectionResult> | null): DeferredPromise<Input, FulfillmentResult | RejectionResult>;
-    catch<Result>(onRejected?: RejectFunction<Result>): DeferredPromise<Input, Output | Result>;
-    finally(onSettled?: (() => void) | null): DeferredPromise<Input, Output>;
+    then<ThenResult = Input, CatchResult = never>(onFulfilled?: (value: Input) => ThenResult | PromiseLike<ThenResult>, onRejected?: (reason: any) => CatchResult | PromiseLike<CatchResult>): DeferredPromise<ThenResult | CatchResult, Output>;
+    catch<CatchResult = never>(onRejected?: (reason: any) => CatchResult | PromiseLike<CatchResult>): DeferredPromise<Input | CatchResult, Output>;
+    finally(onfinally?: () => void | Promise<any>): DeferredPromise<Input, Output>;
 }

build/DeferredPromise.js

@@ -5,28 +5,16 @@ "use strict";
 const createDeferredExecutor_1 = require("./createDeferredExecutor");
-/**
- * @example
- * function getPort() {
- *   const portReadyPromise = new DeferredPromise<number>()
- *   port.on('ready', (port) => portReadyPromise.resolve(port))
- *   port.on('error', (error) => portReadyPromise.reject(error))
- *   returtn portReadyPromise
- * }
- */
-class DeferredPromise {
-    #promise;
+class DeferredPromise extends Promise {
     #executor;
     resolve;
     reject;
-    constructor() {
-        this.#executor = (0, createDeferredExecutor_1.createDeferredExecutor)();
-        this.#promise = new Promise(this.#executor);
+    constructor(executor = null) {
+        const deferredExecutor = (0, createDeferredExecutor_1.createDeferredExecutor)();
+        super((originalResolve, originalReject) => {
+            deferredExecutor(originalResolve, originalReject);
+            executor?.(deferredExecutor.resolve, deferredExecutor.reject);
+        });
+        this.#executor = deferredExecutor;
         this.resolve = this.#executor.resolve;
         this.reject = this.#executor.reject;
     }
-    static get [Symbol.species]() {
-        return Promise;
-    }
-    get [Symbol.toStringTag]() {
-        return 'DeferredPromise';
-    }
     get state() {
@@ -39,89 +27,14 @@ return this.#executor.state;
     then(onFulfilled, onRejected) {
-        const derivedPromise = new DeferredPromise();
-        const resolveDerivedPromise = (result) => {
-            if (typeof onFulfilled === 'function') {
-                try {
-                    const nextResult = onFulfilled(result);
-                    derivedPromise.#executor.resolve(nextResult);
-                }
-                catch (error) {
-                    rejectDerivedPromise(error);
-                }
-                return;
-            }
-            /**
-             * @note Use the executor directly because the "resolve" method
-             * always gets overridden to point to the previous Promise in the chain.
-             */
-            derivedPromise.#executor.resolve(result);
-        };
-        const rejectDerivedPromise = (result) => {
-            if (typeof onRejected === 'function') {
-                try {
-                    const nextReason = onRejected(result);
-                    /**
-                     * @note If the rejection has a handler callback ("catch"),
-                     * resolve the chained promise instead of rejecting it.
-                     * The "catch" callback is there precisely to prevent
-                     * uncaught promise rejection errors.
-                     */
-                    derivedPromise.#executor.resolve(nextReason);
-                    /**
-                     * @note Since the handled rejected promise was resolved internally,
-                     * still mark its state as rejected. Do so in the next microtask
-                     * because executor rejects the promise in the next task as well
-                     */
-                    queueMicrotask(() => {
-                        derivedPromise.#executor.state = 'rejected';
-                        derivedPromise.#executor.rejectionReason = nextReason;
-                    });
-                }
-                catch (error) {
-                    rejectDerivedPromise(error);
-                }
-                return;
-            }
-            derivedPromise.#executor.reject(result);
-        };
-        switch (this.state) {
-            case 'pending': {
-                /**
-                 * @note Override the chainable "resolve" so that when called
-                 * it executes the resolve of the Promise from which it was
-                 * chained from.
-                 *
-                 * @example
-                 * const p1 = new DeferredPromise().then(A).then(B)
-                 * p1.resolve()
-                 *
-                 * Here, "p1" points to the rightmost promise (B) but the
-                 * order of resolving the value must be left-to-right:
-                 * Initial -> A -> B
-                 */
-                derivedPromise.resolve = this.resolve;
-                derivedPromise.reject = this.reject;
-                this.#promise.then(resolveDerivedPromise, rejectDerivedPromise);
-                break;
-            }
-            case 'fulfilled': {
-                resolveDerivedPromise(this.#executor.result);
-                break;
-            }
-            case 'rejected': {
-                rejectDerivedPromise(this.#executor.rejectionReason);
-                break;
-            }
-        }
-        return derivedPromise;
+        return this.#decorate(super.then(onFulfilled, onRejected));
     }
     catch(onRejected) {
-        return this.then(undefined, onRejected);
+        return this.#decorate(super.catch(onRejected));
     }
-    finally(onSettled) {
-        return this.then((result) => {
-            onSettled?.();
-            return result;
-        }, (reason) => {
-            onSettled?.();
-            throw reason;
+    finally(onfinally) {
+        return this.#decorate(super.finally(onfinally));
+    }
+    #decorate(promise) {
+        return Object.defineProperties(promise, {
+            resolve: { configurable: true, value: this.resolve },
+            reject: { configurable: true, value: this.reject },
         });
@@ -128,0 +41,0 @@ }

package.json

 {
   "name": "@open-draft/deferred-promise",
-  "version": "2.0.0",
-  "description": "A Promise that can be resolved/rejected elsewhere",
+  "version": "2.1.0",
+  "description": "A Promise-compatible abstraction that defers resolving/rejecting promises to another closure.",
   "main": "./build/index.js",
@@ -9,2 +9,3 @@ "typings": "./build/index.d.ts",
     "test": "jest",
+    "test:compliance": "export NODE_OPTIONS=--loader=tsx || set NODE_OPTIONS=--loader=tsx&& npx -y promises-aplus-tests ./test/aplus-tests-adapter.ts",
     "prebuild": "rimraf ./build",
@@ -22,3 +23,4 @@ "build": "tsc",
     "resolve",
-    "reject"
+    "reject",
+    "executor"
   ],
@@ -33,4 +35,5 @@ "author": "Artem Zakharchenko",
     "ts-jest": "^29.0.0",
+    "tsx": "^3.12.1",
     "typescript": "^4.8.3"
   }
 }

README.md

@@ -186,1 +186,7 @@ # Deferred Promise
 See [`DeferredExecutor.rejectionReason`](#deferredexecutorrejectionreason)
+
+---
+
+## Mentions
+
+- [Jonas Kuske](https://github.com/jonaskuske) for the phenomenal work around improving Promise-compliance.

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24932

increased by32.6%

Number of package files

14

increased by27.27%

Lines of code

276

increased by30.81%

Number of lines in readme file

192

increased by3.23%

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