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rxjs

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Reactive Extensions for modern JavaScript

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import { Subscriber } from '../Subscriber'; import { isNumeric } from '../util/isNumeric'; import { IScheduler } from '../Scheduler'; import { Observable } from '../Observable'; import { async } from '../scheduler/async'; /** * We need this JSDoc comment for affecting ESDoc. * @extends {Ignored} * @hide true */ export class IntervalObservable extends Observable<number> { /** * Creates an Observable that emits sequential numbers every specified * interval of time, on a specified IScheduler. * * <span class="informal">Emits incremental numbers periodically in time. * </span> * * <img src="./img/interval.png" width="100%"> * * `interval` returns an Observable that emits an infinite sequence of * ascending integers, with a constant interval of time of your choosing * between those emissions. The first emission is not sent immediately, but * only after the first period has passed. By default, this operator uses the * `async` IScheduler to provide a notion of time, but you may pass any * IScheduler to it. * * @example <caption>Emits ascending numbers, one every second (1000ms)</caption> * var numbers = Rx.Observable.interval(1000); * numbers.subscribe(x => console.log(x)); * * @see {@link timer} * @see {@link delay} * * @param {number} [period=0] The interval size in milliseconds (by default) * or the time unit determined by the scheduler's clock. * @param {Scheduler} [scheduler=async] The IScheduler to use for scheduling * the emission of values, and providing a notion of "time". * @return {Observable} An Observable that emits a sequential number each time * interval. * @static true * @name interval * @owner Observable */ static create(period: number = 0, scheduler: IScheduler = async): Observable<number> { return new IntervalObservable(period, scheduler); } static dispatch(state: any): void { const { index, subscriber, period } = state; subscriber.next(index); if (subscriber.closed) { return; } state.index += 1; (<any> this).schedule(state, period); } constructor(private period: number = 0, private scheduler: IScheduler = async) { super(); if (!isNumeric(period) || period < 0) { this.period = 0; } if (!scheduler || typeof scheduler.schedule !== 'function') { this.scheduler = async; } } protected _subscribe(subscriber: Subscriber<number>) { const index = 0; const period = this.period; const scheduler = this.scheduler; subscriber.add(scheduler.schedule(IntervalObservable.dispatch, period, { index, subscriber, period })); } }