01a5f3da90
Reviewed By: mweststrate Differential Revision: D34307356 fbshipit-source-id: 27e61355a85995368ebb197c42d58f4145473567
48 lines
1.1 KiB
TypeScript
48 lines
1.1 KiB
TypeScript
/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @format
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*/
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type Res<T> = {
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promise: Promise<T>;
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resolve: (...res: T extends void ? [] : [T]) => void;
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reject: (reason: unknown) => void;
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} & (
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| {
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state: 'pending';
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promiseVal: undefined;
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}
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| {state: 'resolved'; promiseVal: T}
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| {state: 'rejected'; promiseVal: unknown}
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);
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export const createControlledPromise = <T,>(): Res<T> => {
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let resolve!: Res<T>['resolve'];
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let reject!: Res<T>['reject'];
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let state: 'pending' | 'resolved' | 'rejected' = 'pending';
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let promiseVal: T | unknown | undefined;
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const promise = new Promise<T>((resolveP, rejectP) => {
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resolve = ((val) => {
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state = 'resolved';
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promiseVal = val;
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resolveP(val as T | PromiseLike<T>);
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}) as typeof resolve;
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reject = (err) => {
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state = 'rejected';
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promiseVal = err;
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rejectP(err);
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};
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});
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return {
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promise,
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resolve,
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reject,
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state,
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promiseVal,
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} as Res<T>;
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};
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