70 lines
1.8 KiB
TypeScript
70 lines
1.8 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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import { done } from './util';
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export function debounce(delay: number): Function {
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return decorate((fn, key) => {
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const timerKey = `$debounce$${key}`;
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return function (this: any, ...args: any[]) {
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clearTimeout(this[timerKey]);
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this[timerKey] = setTimeout(() => fn.apply(this, args), delay);
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};
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});
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}
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export const throttle = decorate(_throttle);
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function _throttle<T>(fn: Function, key: string): Function {
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const currentKey = `$throttle$current$${key}`;
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const nextKey = `$throttle$next$${key}`;
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const trigger = function (this: any, ...args: any[]) {
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if (this[nextKey]) {
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return this[nextKey];
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}
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if (this[currentKey]) {
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this[nextKey] = done(this[currentKey]).then(() => {
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this[nextKey] = undefined;
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return trigger.apply(this, args);
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});
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return this[nextKey];
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}
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this[currentKey] = fn.apply(this, args) as Promise<T>;
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const clear = () => this[currentKey] = undefined;
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done(this[currentKey]).then(clear, clear);
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return this[currentKey];
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};
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return trigger;
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}
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function decorate(decorator: (fn: Function, key: string) => Function): Function {
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return (_target: any, key: string, descriptor: any) => {
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let fnKey: string | null = null;
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let fn: Function | null = null;
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if (typeof descriptor.value === 'function') {
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fnKey = 'value';
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fn = descriptor.value;
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} else if (typeof descriptor.get === 'function') {
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fnKey = 'get';
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fn = descriptor.get;
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}
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if (!fn || !fnKey) {
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throw new Error('not supported');
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}
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descriptor[fnKey] = decorator(fn, key);
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};
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}
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