puppeteer-core
Version:
A high-level API to control headless Chrome over the DevTools Protocol
105 lines • 3.01 kB
JavaScript
/**
* @license
* Copyright 2024 Google Inc.
* SPDX-License-Identifier: Apache-2.0
*/
import { TimeoutError } from '../common/Errors.js';
/**
* Creates and returns a deferred object along with the resolve/reject functions.
*
* If the deferred has not been resolved/rejected within the `timeout` period,
* the deferred gets resolves with a timeout error. `timeout` has to be greater than 0 or
* it is ignored.
*
* @internal
*/
export class Deferred {
static create(opts) {
return new Deferred(opts);
}
static async race(awaitables) {
const deferredWithTimeout = new Set();
try {
const promises = awaitables.map(value => {
if (value instanceof Deferred) {
if (value.#timeoutId) {
deferredWithTimeout.add(value);
}
return value.valueOrThrow();
}
return value;
});
// eslint-disable-next-line no-restricted-syntax
return await Promise.race(promises);
}
finally {
for (const deferred of deferredWithTimeout) {
// We need to stop the timeout else
// Node.JS will keep running the event loop till the
// timer executes
deferred.reject(new Error('Timeout cleared'));
}
}
}
#isResolved = false;
#isRejected = false;
#value;
// SAFETY: This is ensured by #taskPromise.
#resolve;
// TODO: Switch to Promise.withResolvers with Node 22
#taskPromise = new Promise(resolve => {
this.#resolve = resolve;
});
#timeoutId;
#timeoutError;
constructor(opts) {
if (opts && opts.timeout > 0) {
this.#timeoutError = new TimeoutError(opts.message);
this.#timeoutId = setTimeout(() => {
this.reject(this.#timeoutError);
}, opts.timeout);
}
}
#finish(value) {
clearTimeout(this.#timeoutId);
this.#value = value;
this.#resolve();
}
resolve(value) {
if (this.#isRejected || this.#isResolved) {
return;
}
this.#isResolved = true;
this.#finish(value);
}
reject(error) {
if (this.#isRejected || this.#isResolved) {
return;
}
this.#isRejected = true;
this.#finish(error);
}
resolved() {
return this.#isResolved;
}
finished() {
return this.#isResolved || this.#isRejected;
}
value() {
return this.#value;
}
#promise;
valueOrThrow() {
if (!this.#promise) {
this.#promise = (async () => {
await this.#taskPromise;
if (this.#isRejected) {
throw this.#value;
}
return this.#value;
})();
}
return this.#promise;
}
}
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