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- import { Subscriber } from '../Subscriber';
- import { async } from '../scheduler/async';
- /**
- * Emits the most recently emitted value from the source Observable within
- * periodic time intervals.
- *
- * <span class="informal">Samples the source Observable at periodic time
- * intervals, emitting what it samples.</span>
- *
- * <img src="./img/sampleTime.png" width="100%">
- *
- * `sampleTime` periodically looks at the source Observable and emits whichever
- * value it has most recently emitted since the previous sampling, unless the
- * source has not emitted anything since the previous sampling. The sampling
- * happens periodically in time every `period` milliseconds (or the time unit
- * defined by the optional `scheduler` argument). The sampling starts as soon as
- * the output Observable is subscribed.
- *
- * @example <caption>Every second, emit the most recent click at most once</caption>
- * var clicks = Rx.Observable.fromEvent(document, 'click');
- * var result = clicks.sampleTime(1000);
- * result.subscribe(x => console.log(x));
- *
- * @see {@link auditTime}
- * @see {@link debounceTime}
- * @see {@link delay}
- * @see {@link sample}
- * @see {@link throttleTime}
- *
- * @param {number} period The sampling period expressed in milliseconds or the
- * time unit determined internally by the optional `scheduler`.
- * @param {Scheduler} [scheduler=async] The {@link IScheduler} to use for
- * managing the timers that handle the sampling.
- * @return {Observable<T>} An Observable that emits the results of sampling the
- * values emitted by the source Observable at the specified time interval.
- * @method sampleTime
- * @owner Observable
- */
- export function sampleTime(period, scheduler = async) {
- return (source) => source.lift(new SampleTimeOperator(period, scheduler));
- }
- class SampleTimeOperator {
- constructor(period, scheduler) {
- this.period = period;
- this.scheduler = scheduler;
- }
- call(subscriber, source) {
- return source.subscribe(new SampleTimeSubscriber(subscriber, this.period, this.scheduler));
- }
- }
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
- class SampleTimeSubscriber extends Subscriber {
- constructor(destination, period, scheduler) {
- super(destination);
- this.period = period;
- this.scheduler = scheduler;
- this.hasValue = false;
- this.add(scheduler.schedule(dispatchNotification, period, { subscriber: this, period }));
- }
- _next(value) {
- this.lastValue = value;
- this.hasValue = true;
- }
- notifyNext() {
- if (this.hasValue) {
- this.hasValue = false;
- this.destination.next(this.lastValue);
- }
- }
- }
- function dispatchNotification(state) {
- let { subscriber, period } = state;
- subscriber.notifyNext();
- this.schedule(state, period);
- }
- //# sourceMappingURL=sampleTime.js.map
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