std@0.139.0/async/abortable.ts

Deno standard library
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abortable.ts
// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.import { deferred } from "./deferred.ts";
/** Make Promise or AsyncIterable abortable with the given signal. */export function abortable<T>(p: Promise<T>, signal: AbortSignal): Promise<T>;export function abortable<T>( p: AsyncIterable<T>, signal: AbortSignal,): AsyncGenerator<T>;export function abortable<T>( p: Promise<T> | AsyncIterable<T>, signal: AbortSignal,): Promise<T> | AsyncIterable<T> { if (p instanceof Promise) { return abortablePromise(p, signal); } else { return abortableAsyncIterable(p, signal); }}
/** Make Promise abortable with the given signal. */export function abortablePromise<T>( p: Promise<T>, signal: AbortSignal,): Promise<T> { if (signal.aborted) { return Promise.reject(createAbortError(signal.reason)); } const waiter = deferred<never>(); const abort = () => waiter.reject(createAbortError(signal.reason)); signal.addEventListener("abort", abort, { once: true }); return Promise.race([ waiter, p.finally(() => { signal.removeEventListener("abort", abort); }), ]);}
/** Make AsyncIterable abortable with the given signal. */export async function* abortableAsyncIterable<T>( p: AsyncIterable<T>, signal: AbortSignal,): AsyncGenerator<T> { if (signal.aborted) { throw createAbortError(signal.reason); } const waiter = deferred<never>(); const abort = () => waiter.reject(createAbortError(signal.reason)); signal.addEventListener("abort", abort, { once: true });
const it = p[Symbol.asyncIterator](); while (true) { const { done, value } = await Promise.race([waiter, it.next()]); if (done) { signal.removeEventListener("abort", abort); return; } yield value; }}
// This `reason` comes from `AbortSignal` thus must be `any`.// deno-lint-ignore no-explicit-anyfunction createAbortError(reason?: any): DOMException { return new DOMException( reason ? `Aborted: ${reason}` : "Aborted", "AbortError", );}