@dxos/async - npm Package Compare versions

Comparing version 1.0.0-beta.7 to 1.0.0-beta.8

dist/es/event.d.ts

@@ -0,1 +1,6 @@
+export declare type Effect = () => (() => void) | undefined;
+interface EventEmitterLike {
+    on(event: string, cb: (data: any) => void): void;
+    off(event: string, cb: (data: any) => void): void;
+}
 /**
@@ -32,4 +37,6 @@ * An EventEmitter variant that does not do event multiplexing and respresents a single event.
 export declare class Event<T = void> implements ReadOnlyEvent<T> {
+    static wrap<T>(emitter: EventEmitterLike, eventName: string): Event<T>;
     private readonly _listeners;
     private readonly _onceListeners;
+    private readonly _effects;
     /**
@@ -46,3 +53,2 @@ * Emit an event.
     emit(data: T): void;
-    private _trigger;
     /**
@@ -96,2 +102,27 @@ * Register an event listener.
     listenerCount(): number;
+    /**
+     * Add a side effect that will be activated once the event has at least one subscriber.
+     * The provided callback can return a function that will be used to clean up after the last subscriber unsubscribes from the event.
+     * The API is similar to `useEffect` from React.
+     *
+     * ## Example:
+     * ```typescript
+     * event.addEffect(() => {
+     *   // do stuff
+     *   return () => {
+     *     // clean-up
+     *   };
+     * });
+     * ```
+     *
+     * @returns Callback that will remove this effect once called.
+     */
+    addEffect(effect: Effect): () => void;
+    /**
+     * Turn any variant of `Event<T>` into an `Event<void>` discarding the callback parameter.
+     */
+    discardParameter(): Event<void>;
+    private _trigger;
+    private _runEffects;
+    private _cleanupEffects;
 }
@@ -148,3 +179,8 @@ /**
     waitForCount(expectedCount: number): Promise<T>;
+    /**
+     * Turn any variant of `Event<T>` into an `Event<void>` discarding the callback parameter.
+     */
+    discardParameter(): Event<void>;
 }
+export {};
 //# sourceMappingURL=event.d.ts.map

dist/es/event.js

@@ -38,3 +38,13 @@ "use strict";
         this._onceListeners = new Set();
+        this._effects = new Set();
     }
+    static wrap(emitter, eventName) {
+        const event = new Event();
+        event.addEffect(() => {
+            const onEvent = (data) => event.emit(data);
+            emitter.on(eventName, onEvent);
+            return () => emitter.off(eventName, onEvent);
+        });
+        return event;
+    }
     /**
@@ -59,12 +69,2 @@ * Emit an event.
     }
-    _trigger(listener, data) {
-        setImmediate(() => {
-            try {
-                listener(data);
-            }
-            catch (err) {
-                console.log(`Unhandled error in Event listener: ${err}`);
-            }
-        });
-    }
     /**
@@ -83,2 +83,5 @@ * Register an event listener.
         this._listeners.add(callback);
+        if (this.listenerCount() === 1) {
+            this._runEffects();
+        }
         return () => this.off(callback);
@@ -98,2 +101,5 @@ }
         this._onceListeners.delete(callback);
+        if (this.listenerCount() === 0) {
+            this._cleanupEffects();
+        }
     }
@@ -112,3 +118,11 @@ /**
         this._onceListeners.add(callback);
-        return () => this._onceListeners.delete(callback);
+        if (this.listenerCount() === 1) {
+            this._runEffects();
+        }
+        return () => {
+            this._onceListeners.delete(callback);
+            if (this.listenerCount() === 0) {
+                this._runEffects();
+            }
+        };
     }
@@ -154,4 +168,63 @@ /**
     }
+    /**
+     * Add a side effect that will be activated once the event has at least one subscriber.
+     * The provided callback can return a function that will be used to clean up after the last subscriber unsubscribes from the event.
+     * The API is similar to `useEffect` from React.
+     *
+     * ## Example:
+     * ```typescript
+     * event.addEffect(() => {
+     *   // do stuff
+     *   return () => {
+     *     // clean-up
+     *   };
+     * });
+     * ```
+     *
+     * @returns Callback that will remove this effect once called.
+     */
+    addEffect(effect) {
+        const handle = { effect, cleanup: undefined };
+        if (this.listenerCount() > 0) {
+            handle.cleanup = handle.effect();
+        }
+        this._effects.add(handle);
+        return () => {
+            var _a;
+            // eslint-disable-next-line no-unused-expressions
+            (_a = handle.cleanup) === null || _a === void 0 ? void 0 : _a.call(handle);
+            this._effects.delete(handle);
+        };
+    }
+    /**
+     * Turn any variant of `Event<T>` into an `Event<void>` discarding the callback parameter.
+     */
+    discardParameter() {
+        return this;
+    }
+    _trigger(listener, data) {
+        setImmediate(() => {
+            try {
+                listener(data);
+            }
+            catch (err) {
+                console.log(`Unhandled error in Event listener: ${err}`);
+            }
+        });
+    }
+    _runEffects() {
+        for (const handle of this._effects) {
+            handle.cleanup = handle.effect();
+        }
+    }
+    _cleanupEffects() {
+        var _a;
+        for (const handle of this._effects) {
+            // eslint-disable-next-line no-unused-expressions
+            (_a = handle.cleanup) === null || _a === void 0 ? void 0 : _a.call(handle);
+            handle.cleanup = undefined;
+        }
+    }
 }
 exports.Event = Event;
 //# sourceMappingURL=event.js.map

dist/es/lock.d.ts

@@ -11,2 +11,4 @@ /**
  * and it's not async while still returning a promise.
+ *
+ * Java docs reference on synchronized sections: https://docs.oracle.com/javase/tutorial/essential/concurrency/locksync.html
  */
@@ -13,0 +15,0 @@ export declare class Lock {

dist/es/lock.js

@@ -14,2 +14,4 @@ "use strict";
  * and it's not async while still returning a promise.
+ *
+ * Java docs reference on synchronized sections: https://docs.oracle.com/javase/tutorial/essential/concurrency/locksync.html
  */
@@ -16,0 +18,0 @@ class Lock {

package.json

 {
   "name": "@dxos/async",
-  "version": "1.0.0-beta.7",
+  "version": "1.0.0-beta.8",
   "description": "Basic async utils",
@@ -5,0 +5,0 @@ "files": [

New alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Fixed alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Improved metrics

Total package byte prevSize

95800

increased by6.64%

Lines of code

991

increased by12.87%

No dependency changes