jdefer - npm Package Compare versions

Comparing version 0.0.14 to 0.1.0

index.d.ts

@@ -25,1 +25,11 @@ export interface IDefer<T> {
 export declare function makeBroadcastStream<T>(): IBroadcastStream<T>;
+
+export interface ISingleStream<T> extends AsyncIterable<T> {
+	next(value: T): void;
+
+	throw(error: unknown): void;
+
+	done(): void;
+}
+
+export declare function makeSingleStream<T>(): ISingleStream<T>;

index.js

@@ -1,11 +0,14 @@
-"use strict";
-Object.defineProperty(exports, "__esModule", { value: true });
-exports.makeBroadcastStream = void 0;
+'use strict'
+Object.defineProperty(exports, '__esModule', {value: true})
+exports.default = makeDefer
+exports.makeBroadcastStream = makeBroadcastStream
+exports.makeSingleStream = makeSingleStream
+
 function makeDefer() {
-	let resolve = undefined;
-	let reject = undefined;
+	let resolve = undefined
+	let reject = undefined
 	const promise = new Promise((rs, rj) => {
-		resolve = rs;
-		reject = rj;
-	});
+		resolve = rs
+		reject = rj
+	})
 	return {
@@ -15,9 +18,9 @@ resolve,
 		promise
-	};
+	}
 }
-exports.default = makeDefer;
+
 function makeBroadcastStream() {
-	const listeners = [];
-	let done = false;
-	let defer = makeDefer();
+	const listeners = []
+	let done = false
+	let defer = makeDefer()
 	return {
@@ -27,59 +30,124 @@ [Symbol.asyncIterator]() {
 				async next() {
-					const value = await defer.promise;
-					defer = makeDefer();
-					return value;
+					if (done)
+						return {value: undefined, done: true}
+					const value = await defer.promise
+					defer = makeDefer()
+					return value
 				},
 				async return(value) {
-					return { value: undefined, done: true };
+					return {value: undefined, done: true}
 				},
 				async throw(e) {
-					return { value: undefined, done: true };
+					return {value: undefined, done: true}
 				}
-			};
+			}
 		},
-		listen(onNext, { onError, onDone } = {}) {
-			if (done)
-				throw new Error('Cannot listen after done');
-			const listener = { onNext, onError, onDone };
-			listeners.push(listener);
+		listen(onNext, {onError, onDone} = {}) {
+			if (done) {
+				onDone?.()
+				return () => {
+				}
+			}
+			const listener = {onNext, onError, onDone}
+			listeners.push(listener)
 			return function removeListener() {
-				const idx = listeners.lastIndexOf(listener);
+				const idx = listeners.lastIndexOf(listener)
 				if (idx >= 0)
-					listeners.splice(idx, 1);
-			};
+					listeners.splice(idx, 1)
+			}
 		},
 		next(value) {
 			if (done)
-				throw new Error('Cannot next after done');
-			defer.resolve({ value, done: false });
-			for (const { onNext } of listeners)
+				return
+			defer.resolve({value, done: false})
+			for (const {onNext} of listeners)
 				try {
-					onNext(value);
+					onNext(value)
+				} catch {
 				}
-				catch { }
 		},
 		throw(error) {
 			if (done)
-				throw new Error('Cannot throw after done');
-			done = true;
-			defer.reject(error);
-			for (const { onError } of listeners)
+				return
+			done = true
+			defer.reject(error)
+			for (const {onError} of listeners)
 				try {
-					onError?.(error);
+					onError?.(error)
+				} catch {
 				}
-				catch { }
 		},
 		done() {
 			if (done)
-				throw new Error('Cannot done after done');
-			done = true;
-			defer.resolve({ value: undefined, done: true });
-			for (const { onDone } of listeners)
+				return
+			done = true
+			defer.resolve({value: undefined, done: true})
+			for (const {onDone} of listeners)
 				try {
-					onDone?.();
+					onDone?.()
+				} catch {
 				}
-				catch { }
 		},
-	};
+	}
 }
-exports.makeBroadcastStream = makeBroadcastStream;
+
+function makeSingleStream() {
+	// at least one of chunk or defers is empty, all the time
+	const chunk = []
+	const defers = []
+	let done = false
+	let error
+	return {
+		[Symbol.asyncIterator]() {
+			return {
+				async next() {
+					if (chunk.length)
+						return chunk.shift()
+					if (done) {
+						if (error)
+							throw error
+						return {value: undefined, done: true}
+					}
+					// chunk must currently be empty, it is safe to make defers non-empty
+					const defer = makeDefer()
+					defers.push(defer)
+					return defer.promise
+				},
+				async return(value) {
+					return {value: undefined, done: true}
+				},
+				async throw(e) {
+					return {value: undefined, done: true}
+				}
+			}
+		},
+		next(value) {
+			if (done)
+				return
+			if (defers.length) {
+				const defer = defers.shift()
+				defer.resolve({value, done: false})
+				return
+			}
+			// defers must currently be empty, it is safe to make chunk non-empty
+			chunk.push({value, done: false})
+		},
+		throw(err) {
+			if (done)
+				return
+			done = true
+			error = err
+			for (const defer of defers)
+				defer.reject(err)
+			defers.length = 0
+		},
+		done() {
+			if (done)
+				return
+			done = true
+			for (const defer of defers)
+				defer.resolve({value: undefined, done: true})
+			defers.length = 0
+		},
+	}
+}

package.json

 {
 	"name": "jdefer",
-	"version": "0.0.14",
+	"version": "0.1.0",
 	"main": "index.js",
@@ -5,0 +5,0 @@ "repository": "https://github.com/tranvansang/jdefer",

README.md

@@ -13,2 +13,4 @@ # Javascript promise defer library
 
+In 2024: recommended using [`Promise.withResolvers()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/withResolvers).
+
 ```typescript
@@ -15,0 +17,0 @@ import makeDefer from 'jdefer'

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Improved metrics

Total package byte prevSize

8727

increased by50.39%

Lines of code

313

increased by76.84%

Number of lines in readme file

68

increased by3.03%

No dependency changes