work.suroh.tk/node_modules/rxjs/_esm2015/observable/IntervalObservable.js

75 lines
2.7 KiB
JavaScript

import { isNumeric } from '../util/isNumeric';
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 {
constructor(period = 0, scheduler = async) {
super();
this.period = period;
this.scheduler = scheduler;
if (!isNumeric(period) || period < 0) {
this.period = 0;
}
if (!scheduler || typeof scheduler.schedule !== 'function') {
this.scheduler = async;
}
}
/**
* 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 = 0, scheduler = async) {
return new IntervalObservable(period, scheduler);
}
static dispatch(state) {
const { index, subscriber, period } = state;
subscriber.next(index);
if (subscriber.closed) {
return;
}
state.index += 1;
this.schedule(state, period);
}
/** @deprecated internal use only */ _subscribe(subscriber) {
const index = 0;
const period = this.period;
const scheduler = this.scheduler;
subscriber.add(scheduler.schedule(IntervalObservable.dispatch, period, {
index, subscriber, period
}));
}
}
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