| 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 |