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- import { Subscriber } from '../Subscriber';
- import { async } from '../scheduler/async';
- /**
- * Emits a value from the source Observable only after a particular time span
- * has passed without another source emission.
- *
- * <span class="informal">It's like {@link delay}, but passes only the most
- * recent value from each burst of emissions.</span>
- *
- * <img src="./img/debounceTime.png" width="100%">
- *
- * `debounceTime` delays values emitted by the source Observable, but drops
- * previous pending delayed emissions if a new value arrives on the source
- * Observable. This operator keeps track of the most recent value from the
- * source Observable, and emits that only when `dueTime` enough time has passed
- * without any other value appearing on the source Observable. If a new value
- * appears before `dueTime` silence occurs, the previous value will be dropped
- * and will not be emitted on the output Observable.
- *
- * This is a rate-limiting operator, because it is impossible for more than one
- * value to be emitted in any time window of duration `dueTime`, but it is also
- * a delay-like operator since output emissions do not occur at the same time as
- * they did on the source Observable. Optionally takes a {@link IScheduler} for
- * managing timers.
- *
- * @example <caption>Emit the most recent click after a burst of clicks</caption>
- * var clicks = Rx.Observable.fromEvent(document, 'click');
- * var result = clicks.debounceTime(1000);
- * result.subscribe(x => console.log(x));
- *
- * @see {@link auditTime}
- * @see {@link debounce}
- * @see {@link delay}
- * @see {@link sampleTime}
- * @see {@link throttleTime}
- *
- * @param {number} dueTime The timeout duration in milliseconds (or the time
- * unit determined internally by the optional `scheduler`) for the window of
- * time required to wait for emission silence before emitting the most recent
- * source value.
- * @param {Scheduler} [scheduler=async] The {@link IScheduler} to use for
- * managing the timers that handle the timeout for each value.
- * @return {Observable} An Observable that delays the emissions of the source
- * Observable by the specified `dueTime`, and may drop some values if they occur
- * too frequently.
- * @method debounceTime
- * @owner Observable
- */
- export function debounceTime(dueTime, scheduler = async) {
- return (source) => source.lift(new DebounceTimeOperator(dueTime, scheduler));
- }
- class DebounceTimeOperator {
- constructor(dueTime, scheduler) {
- this.dueTime = dueTime;
- this.scheduler = scheduler;
- }
- call(subscriber, source) {
- return source.subscribe(new DebounceTimeSubscriber(subscriber, this.dueTime, this.scheduler));
- }
- }
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
- class DebounceTimeSubscriber extends Subscriber {
- constructor(destination, dueTime, scheduler) {
- super(destination);
- this.dueTime = dueTime;
- this.scheduler = scheduler;
- this.debouncedSubscription = null;
- this.lastValue = null;
- this.hasValue = false;
- }
- _next(value) {
- this.clearDebounce();
- this.lastValue = value;
- this.hasValue = true;
- this.add(this.debouncedSubscription = this.scheduler.schedule(dispatchNext, this.dueTime, this));
- }
- _complete() {
- this.debouncedNext();
- this.destination.complete();
- }
- debouncedNext() {
- this.clearDebounce();
- if (this.hasValue) {
- this.destination.next(this.lastValue);
- this.lastValue = null;
- this.hasValue = false;
- }
- }
- clearDebounce() {
- const debouncedSubscription = this.debouncedSubscription;
- if (debouncedSubscription !== null) {
- this.remove(debouncedSubscription);
- debouncedSubscription.unsubscribe();
- this.debouncedSubscription = null;
- }
- }
- }
- function dispatchNext(subscriber) {
- subscriber.debouncedNext();
- }
- //# sourceMappingURL=debounceTime.js.map
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