75 строки
2.6 KiB
TypeScript
75 строки
2.6 KiB
TypeScript
/*---------------------------------------------------------------------------------------------
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* Copyright (c) Microsoft Corporation. All rights reserved.
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* Licensed under the MIT License. See License.txt in the project root for license information.
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*--------------------------------------------------------------------------------------------*/
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/**
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* A manually (or externally) controlled asynchronous Promise implementation
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*/
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export class ManualPromise<T> implements Promise<T> {
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/**
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* Attaches callbacks for the resolution and/or rejection of the Promise.
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* @param onfulfilled The callback to execute when the Promise is resolved.
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* @param onrejected The callback to execute when the Promise is rejected.
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* @returns A Promise for the completion of which ever callback is executed.
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*/
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then<TResult1 = T, TResult2 = never>(onfulfilled?: ((value: T) => TResult1 | PromiseLike<TResult1>) | null | undefined, onrejected?: ((reason: any) => TResult2 | PromiseLike<TResult2>) | null | undefined): Promise<TResult1 | TResult2> {
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return this.p.then(onfulfilled, onrejected);
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}
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/**
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* Attaches a callback for only the rejection of the Promise.
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* @param onrejected The callback to execute when the Promise is rejected.
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* @returns A Promise for the completion of the callback.
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*/
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catch<TResult = never>(onrejected?: ((reason: any) => TResult | PromiseLike<TResult>) | null | undefined): Promise<T | TResult> {
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return this.p.catch(onrejected);
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}
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finally(onfinally?: (() => void) | null | undefined): Promise<T> {
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return this.p.finally(onfinally);
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}
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readonly [Symbol.toStringTag]: 'Promise';
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private p: Promise<T>;
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/**
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* A method to manually resolve the Promise.
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*/
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public resolve: (value?: T | PromiseLike<T> | undefined) => void = (v) => { };
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/**
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* A method to manually reject the Promise
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*/
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public reject: (e: any) => void = (e) => { };
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private state: 'pending' | 'resolved' | 'rejected' = 'pending';
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/**
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* Returns true of the Promise has been Resolved or Rejected
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*/
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public get isCompleted(): boolean {
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return this.state !== 'pending';
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}
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/**
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* Returns true if the Promise has been Resolved.
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*/
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public get isResolved(): boolean {
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return this.state === 'resolved';
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}
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/**
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* Returns true if the Promise has been Rejected.
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*/
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public get isRejected(): boolean {
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return this.state === 'rejected';
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}
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public constructor() {
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this.p = new Promise<T>((r, j) => {
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this.resolve = (v: T | PromiseLike<T> | undefined) => { this.state = 'resolved'; r(v as any); };
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this.reject = (e: any) => { this.state = 'rejected'; j(e); };
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});
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}
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}
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