mirror of https://github.com/denoland/deno.git
27 lines
1.0 KiB
TypeScript
27 lines
1.0 KiB
TypeScript
// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
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// TODO(ry) It'd be better to make Deferred a class that inherits from
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// Promise, rather than an interface. This is possible in ES2016, however
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// typescript produces broken code when targeting ES5 code.
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// See https://github.com/Microsoft/TypeScript/issues/15202
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// At the time of writing, the github issue is closed but the problem remains.
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export interface Deferred<T> extends Promise<T> {
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resolve: (value?: T | PromiseLike<T>) => void;
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// deno-lint-ignore no-explicit-any
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reject: (reason?: any) => void;
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}
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/** Creates a Promise with the `reject` and `resolve` functions
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* placed as methods on the promise object itself. It allows you to do:
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*
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* const p = deferred<number>();
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* // ...
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* p.resolve(42);
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*/
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export function deferred<T>(): Deferred<T> {
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let methods;
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const promise = new Promise<T>((resolve, reject): void => {
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methods = { resolve, reject };
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});
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return Object.assign(promise, methods) as Deferred<T>;
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}
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