104 lines
3.9 KiB
JavaScript
104 lines
3.9 KiB
JavaScript
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import { Subscriber } from '../Subscriber';
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import { async } from '../scheduler/async';
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import { defaultThrottleConfig } from './throttle';
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/**
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* Emits a value from the source Observable, then ignores subsequent source
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* values for `duration` milliseconds, then repeats this process.
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*
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* <span class="informal">Lets a value pass, then ignores source values for the
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* next `duration` milliseconds.</span>
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*
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* <img src="./img/throttleTime.png" width="100%">
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*
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* `throttleTime` emits the source Observable values on the output Observable
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* when its internal timer is disabled, and ignores source values when the timer
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* is enabled. Initially, the timer is disabled. As soon as the first source
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* value arrives, it is forwarded to the output Observable, and then the timer
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* is enabled. After `duration` milliseconds (or the time unit determined
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* internally by the optional `scheduler`) has passed, the timer is disabled,
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* and this process repeats for the next source value. Optionally takes a
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* {@link IScheduler} for managing timers.
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*
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* @example <caption>Emit clicks at a rate of at most one click per second</caption>
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* var clicks = Rx.Observable.fromEvent(document, 'click');
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* var result = clicks.throttleTime(1000);
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* result.subscribe(x => console.log(x));
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*
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* @see {@link auditTime}
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* @see {@link debounceTime}
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* @see {@link delay}
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* @see {@link sampleTime}
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* @see {@link throttle}
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*
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* @param {number} duration Time to wait before emitting another value after
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* emitting the last value, measured in milliseconds or the time unit determined
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* internally by the optional `scheduler`.
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* @param {Scheduler} [scheduler=async] The {@link IScheduler} to use for
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* managing the timers that handle the throttling.
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* @return {Observable<T>} An Observable that performs the throttle operation to
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* limit the rate of emissions from the source.
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* @method throttleTime
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* @owner Observable
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*/
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export function throttleTime(duration, scheduler = async, config = defaultThrottleConfig) {
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return (source) => source.lift(new ThrottleTimeOperator(duration, scheduler, config.leading, config.trailing));
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}
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class ThrottleTimeOperator {
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constructor(duration, scheduler, leading, trailing) {
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this.duration = duration;
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this.scheduler = scheduler;
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this.leading = leading;
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this.trailing = trailing;
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}
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call(subscriber, source) {
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return source.subscribe(new ThrottleTimeSubscriber(subscriber, this.duration, this.scheduler, this.leading, this.trailing));
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}
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}
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/**
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* We need this JSDoc comment for affecting ESDoc.
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* @ignore
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* @extends {Ignored}
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*/
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class ThrottleTimeSubscriber extends Subscriber {
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constructor(destination, duration, scheduler, leading, trailing) {
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super(destination);
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this.duration = duration;
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this.scheduler = scheduler;
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this.leading = leading;
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this.trailing = trailing;
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this._hasTrailingValue = false;
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this._trailingValue = null;
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}
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_next(value) {
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if (this.throttled) {
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if (this.trailing) {
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this._trailingValue = value;
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this._hasTrailingValue = true;
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}
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}
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else {
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this.add(this.throttled = this.scheduler.schedule(dispatchNext, this.duration, { subscriber: this }));
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if (this.leading) {
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this.destination.next(value);
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}
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}
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}
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clearThrottle() {
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const throttled = this.throttled;
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if (throttled) {
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if (this.trailing && this._hasTrailingValue) {
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this.destination.next(this._trailingValue);
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this._trailingValue = null;
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this._hasTrailingValue = false;
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}
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throttled.unsubscribe();
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this.remove(throttled);
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this.throttled = null;
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}
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}
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}
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function dispatchNext(arg) {
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const { subscriber } = arg;
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subscriber.clearThrottle();
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}
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//# sourceMappingURL=throttleTime.js.map
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