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

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2019-12-02 12:22:45 +00:00
import { isNumeric } from '../util/isNumeric';
import { Observable } from '../Observable';
import { async } from '../scheduler/async';
import { isScheduler } from '../util/isScheduler';
import { isDate } from '../util/isDate';
/**
* We need this JSDoc comment for affecting ESDoc.
* @extends {Ignored}
* @hide true
*/
export class TimerObservable extends Observable {
constructor(dueTime = 0, period, scheduler) {
super();
this.period = -1;
this.dueTime = 0;
if (isNumeric(period)) {
this.period = Number(period) < 1 && 1 || Number(period);
}
else if (isScheduler(period)) {
scheduler = period;
}
if (!isScheduler(scheduler)) {
scheduler = async;
}
this.scheduler = scheduler;
this.dueTime = isDate(dueTime) ?
(+dueTime - this.scheduler.now()) :
dueTime;
}
/**
* Creates an Observable that starts emitting after an `initialDelay` and
* emits ever increasing numbers after each `period` of time thereafter.
*
* <span class="informal">Its like {@link interval}, but you can specify when
* should the emissions start.</span>
*
* <img src="./img/timer.png" width="100%">
*
* `timer` returns an Observable that emits an infinite sequence of ascending
* integers, with a constant interval of time, `period` of your choosing
* between those emissions. The first emission happens after the specified
* `initialDelay`. The initial delay may be a {@link Date}. By default, this
* operator uses the `async` IScheduler to provide a notion of time, but you
* may pass any IScheduler to it. If `period` is not specified, the output
* Observable emits only one value, `0`. Otherwise, it emits an infinite
* sequence.
*
* @example <caption>Emits ascending numbers, one every second (1000ms), starting after 3 seconds</caption>
* var numbers = Rx.Observable.timer(3000, 1000);
* numbers.subscribe(x => console.log(x));
*
* @example <caption>Emits one number after five seconds</caption>
* var numbers = Rx.Observable.timer(5000);
* numbers.subscribe(x => console.log(x));
*
* @see {@link interval}
* @see {@link delay}
*
* @param {number|Date} initialDelay The initial delay time to wait before
* emitting the first value of `0`.
* @param {number} [period] The period of time between emissions of the
* subsequent numbers.
* @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 `0` after the
* `initialDelay` and ever increasing numbers after each `period` of time
* thereafter.
* @static true
* @name timer
* @owner Observable
*/
static create(initialDelay = 0, period, scheduler) {
return new TimerObservable(initialDelay, period, scheduler);
}
static dispatch(state) {
const { index, period, subscriber } = state;
const action = this;
subscriber.next(index);
if (subscriber.closed) {
return;
}
else if (period === -1) {
return subscriber.complete();
}
state.index = index + 1;
action.schedule(state, period);
}
/** @deprecated internal use only */ _subscribe(subscriber) {
const index = 0;
const { period, dueTime, scheduler } = this;
return scheduler.schedule(TimerObservable.dispatch, dueTime, {
index, period, subscriber
});
}
}
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