Blame · timer.ts

b69ab31	1	/**
b69ab31	2	* Copyright (c) Meta Platforms, Inc. and affiliates.
b69ab31	3	*
b69ab31	4	* This source code is licensed under the MIT license found in the
b69ab31	5	* LICENSE file in the root directory of this source tree.
b69ab31	6	*/
b69ab31	7
b69ab31	8	import type {Disposable} from './types';
b69ab31	9
b69ab31	10	export class Timer implements Disposable {
b69ab31	11	private timerId: null \| number = null;
b69ab31	12	private disposed = false;
b69ab31	13	private callback: () => void;
b69ab31	14
b69ab31	15	/**
b69ab31	16	* The `callback` can return `false` to auto-stop the timer.
b69ab31	17	* The timer auto stops if being GC-ed.
b69ab31	18	*/
b69ab31	19	constructor(
b69ab31	20	callback: () => void \| boolean,
b69ab31	21	public intervalMs = 1000,
b69ab31	22	enabled = false,
b69ab31	23	) {
b69ab31	24	const thisRef = new WeakRef(this);
b69ab31	25	this.callback = () => {
b69ab31	26	const timer = thisRef.deref();
b69ab31	27	if (timer == null) {
b69ab31	28	// The "timer" object is GC-ed. Do not run this interval.
b69ab31	29	return;
b69ab31	30	}
b69ab31	31	// Run the callback and schedules the next interval.
b69ab31	32	timer.timerId = null;
b69ab31	33	const shouldContinue = callback();
b69ab31	34	if (shouldContinue !== false) {
b69ab31	35	timer.enabled = true;
b69ab31	36	}
b69ab31	37	};
b69ab31	38	this.enabled = enabled;
b69ab31	39	}
b69ab31	40
b69ab31	41	set enabled(value: boolean) {
b69ab31	42	if (value && this.timerId === null && !this.disposed) {
b69ab31	43	this.timerId = window.setTimeout(this.callback, this.intervalMs);
b69ab31	44	} else if (!value && this.timerId !== null) {
b69ab31	45	window.clearTimeout(this.timerId);
b69ab31	46	this.timerId = null;
b69ab31	47	}
b69ab31	48	}
b69ab31	49
b69ab31	50	get enabled(): boolean {
b69ab31	51	return this.timerId !== null;
b69ab31	52	}
b69ab31	53
b69ab31	54	dispose(): void {
b69ab31	55	this.enabled = false;
b69ab31	56	this.disposed = true;
b69ab31	57	}
b69ab31	58	}