parallel-universe/timeout.js

The set of async flow control structures and promise utils.

'use strict';

var AbortablePromise = require('./AbortablePromise.js');
var utils = require('./utils.js');

/**
 * Returns a promise that is fulfilled with a produced value, or rejected after the timeout elapses.
 *
 * @param cb A callback that receives a signal that is aborted if the timeout elapses, or a promise-like object.
 * @param ms The timeout after which the returned promise is rejected.
 * @returns The promise that is fulfilled before a timeout elapses, or rejected with a
 * {@link https://developer.mozilla.org/en-US/docs/Web/API/DOMException#timeouterror TimeoutError}.
 * @template T The value returned from the callback or promise.
 */
function timeout(cb, ms) {
    if (typeof cb !== 'function') {
        return timeout(() => cb, ms);
    }
    return new AbortablePromise.AbortablePromise((resolve, reject, signal) => {
        const timer = setTimeout(() => {
            reject(new DOMException('', 'TimeoutError'));
        }, ms);
        signal.addEventListener('abort', () => {
            clearTimeout(timer);
        });
        new Promise(resolve => {
            resolve(utils.withSignal(cb(signal), signal));
        }).then(value => {
            clearTimeout(timer);
            resolve(value);
        }, reason => {
            clearTimeout(timer);
            reject(reason);
        });
    });
}

exports.timeout = timeout;