Cancellable Events and Promises

cancel.js

/**
 * @param {EventTarget} target
 * @param {string} eventType
 * @param {number?} delayInMs
 * @returns {Promise<Event>}
 */
function eventTimeout(target, eventType, delayInMs = null) {
	const abortController = new AbortController(),
		signal = abortController.signal;

	let timer;
	if (typeof delayInMs === "number") {
		timer = setTimeout(() => {
			if (!signal.aborted)
				abortController.abort(new Error(`${eventType} was not fired within ${delayInMs}ms.`));
		}, delayInMs);
	}

	return cancellableEvent(target, eventType, signal).finally(() => clearTimeout(timer));
}

/**
 * @param {EventTarget} target
 * @param {string} eventType
 * @param {AbortSignal?} signal
 * @returns {Promise<Event>}
 */
function cancellableEvent(target, eventType, signal = null) {
	return new Promise((res, rej) => {
		if (signal) signal.onabort = () => rej(signal.reason);
		target.addEventListener(eventType, (event) => res(event), {
			once: true,
			signal,
		});
	});
}

/**
 * @param {Promise} promise
 * @param {number?} delayInMs
 * @returns {Promise}
 */
function promiseTimeout(promise, delayInMs = null) {
	const abortController = new AbortController(),
		signal = abortController.signal;

	let timer;
	if (typeof delayInMs === "number") {
		timer = setTimeout(() => {
			if (!signal.aborted)
				abortController.abort(new Error(`The Promise was not resolved within ${delayInMs}ms.`));
		}, delayInMs);
	}

	return cancellablePromise(promise, signal).finally(() => clearTimeout(timer));
}

/**
 * @param {Promise} promise
 * @param {AbortSignal?} signal
 * @returns {Promise}
 */
function cancellablePromise(promise, signal = null) {
	return new Promise((res, rej) => {
		if (signal) signal.onabort = () => rej(signal.reason);
		promise.then(res).catch(rej);
	});
}