Support AbortController (#26)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

index.d.ts

@@ -41,6 +41,31 @@ export type Options = {
 		setTimeout: typeof global.setTimeout;
 		clearTimeout: typeof global.clearTimeout;
 	};
+
+	/**
+	You can abort the promise using [`AbortController`](https://developer.mozilla.org/en-US/docs/Web/API/AbortController).
+
+	_Requires Node.js 16 or later._
+
+	@example
+	```
+	import pTimeout from 'p-timeout';
+	import delay from 'delay';
+
+	const delayedPromise = delay(3000);
+
+	const abortController = new AbortController();
+
+	setTimeout(() => {
+		abortController.abort();
+	}, 100);
+
+	await pTimeout(delayedPromise, 2000, undefined, {
+		signal: abortController.signal
+	});
+	```
+	*/
+	signal?: globalThis.AbortSignal;
 };
 
 /**

index.js

@@ -5,8 +5,39 @@ export class TimeoutError extends Error {
 	}
 }
 
+/**
+An error to be thrown when the request is aborted by AbortController.
+DOMException is thrown instead of this Error when DOMException is available.
+*/
+export class AbortError extends Error {
+	constructor(message) {
+		super();
+		this.name = 'AbortError';
+		this.message = message;
+	}
+}
+
+/**
+TODO: Remove AbortError and just throw DOMException when targeting Node 18.
+*/
+const getDOMException = errorMessage => globalThis.DOMException === undefined ?
+	new AbortError(errorMessage) :
+	new DOMException(errorMessage);
+
+/**
+TODO: Remove below function and just 'reject(signal.reason)' when targeting Node 18.
+*/
+const getAbortedReason = signal => {
+	const reason = signal.reason === undefined ?
+		getDOMException('This operation was aborted.') :
+		signal.reason;
+
+	return reason instanceof Error ? reason : getDOMException(reason);
+};
+
 export default function pTimeout(promise, milliseconds, fallback, options) {
 	let timer;
+
 	const cancelablePromise = new Promise((resolve, reject) => {
 		if (typeof milliseconds !== 'number' || Math.sign(milliseconds) !== 1) {
 			throw new TypeError(`Expected \`milliseconds\` to be a positive number, got \`${milliseconds}\``);
@@ -22,6 +53,17 @@ export default function pTimeout(promise, milliseconds, fallback, options) {
 			...options
 		};
 
+		if (options.signal) {
+			const {signal} = options;
+			if (signal.aborted) {
+				reject(getAbortedReason(signal));
+			}
+
+			signal.addEventListener('abort', () => {
+				reject(getAbortedReason(signal));
+			});
+		}
+
 		timer = options.customTimers.setTimeout.call(undefined, () => {
 			if (typeof fallback === 'function') {
 				try {

readme.md

@@ -103,6 +103,31 @@ await pTimeout(doSomething(), 2000, undefined, {
 });
 ```
 
+#### signal
+
+Type: [`AbortSignal`](https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal)
+
+You can abort the promise using [`AbortController`](https://developer.mozilla.org/en-US/docs/Web/API/AbortController).
+
+*Requires Node.js 16 or later.*
+
+```js
+import pTimeout from 'p-timeout';
+import delay from 'delay';
+
+const delayedPromise = delay(3000);
+
+const abortController = new AbortController();
+
+setTimeout(() => {
+	abortController.abort();
+}, 100);
+
+await pTimeout(delayedPromise, 2000, undefined, {
+	signal: abortController.signal
+});
+```
+
 ### TimeoutError
 
 Exposed for instance checking and sub-classing.

test.js

@@ -88,3 +88,34 @@ test('`.clear()` method', async t => {
 	await promise;
 	t.true(inRange(end(), {start: 0, end: 350}));
 });
+
+/**
+TODO: Remove if statement when targeting Node.js 16.
+*/
+if (globalThis.AbortController !== undefined) {
+	test('rejects when calling `AbortController#abort()`', async t => {
+		const abortController = new AbortController();
+
+		const promise = pTimeout(delay(3000), 2000, undefined, {
+			signal: abortController.signal
+		});
+
+		abortController.abort();
+
+		await t.throwsAsync(promise, {
+			name: 'AbortError'
+		});
+	});
+
+	test('already aborted signal', async t => {
+		const abortController = new AbortController();
+
+		abortController.abort();
+
+		await t.throwsAsync(pTimeout(delay(3000), 2000, undefined, {
+			signal: abortController.signal
+		}), {
+			name: 'AbortError'
+		});
+	});
+}