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- import { Subscriber } from '../Subscriber';
- import { MonoTypeOperatorFunction, ObservableInput } from '../types';
- import { operate } from '../util/lift';
- import { innerFrom } from '../observable/innerFrom';
- import { createOperatorSubscriber } from './OperatorSubscriber';
- /**
- * Ignores source values for a duration determined by another Observable, then
- * emits the most recent value from the source Observable, then repeats this
- * process.
- *
- * <span class="informal">It's like {@link auditTime}, but the silencing
- * duration is determined by a second Observable.</span>
- *
- * 
- *
- * `audit` is similar to `throttle`, but emits the last value from the silenced
- * time window, instead of the first value. `audit` emits the most recent value
- * from the source Observable on the output Observable as soon as its internal
- * timer becomes disabled, and ignores source values while the timer is enabled.
- * Initially, the timer is disabled. As soon as the first source value arrives,
- * the timer is enabled by calling the `durationSelector` function with the
- * source value, which returns the "duration" Observable. When the duration
- * Observable emits a value, the timer is disabled, then the most
- * recent source value is emitted on the output Observable, and this process
- * repeats for the next source value.
- *
- * ## Example
- *
- * Emit clicks at a rate of at most one click per second
- *
- * ```ts
- * import { fromEvent, audit, interval } from 'rxjs';
- *
- * const clicks = fromEvent(document, 'click');
- * const result = clicks.pipe(audit(ev => interval(1000)));
- * result.subscribe(x => console.log(x));
- * ```
- *
- * @see {@link auditTime}
- * @see {@link debounce}
- * @see {@link delayWhen}
- * @see {@link sample}
- * @see {@link throttle}
- *
- * @param durationSelector A function
- * that receives a value from the source Observable, for computing the silencing
- * duration, returned as an Observable or a Promise.
- * @return A function that returns an Observable that performs rate-limiting of
- * emissions from the source Observable.
- */
- export function audit<T>(durationSelector: (value: T) => ObservableInput<any>): MonoTypeOperatorFunction<T> {
- return operate((source, subscriber) => {
- let hasValue = false;
- let lastValue: T | null = null;
- let durationSubscriber: Subscriber<any> | null = null;
- let isComplete = false;
- const endDuration = () => {
- durationSubscriber?.unsubscribe();
- durationSubscriber = null;
- if (hasValue) {
- hasValue = false;
- const value = lastValue!;
- lastValue = null;
- subscriber.next(value);
- }
- isComplete && subscriber.complete();
- };
- const cleanupDuration = () => {
- durationSubscriber = null;
- isComplete && subscriber.complete();
- };
- source.subscribe(
- createOperatorSubscriber(
- subscriber,
- (value) => {
- hasValue = true;
- lastValue = value;
- if (!durationSubscriber) {
- innerFrom(durationSelector(value)).subscribe(
- (durationSubscriber = createOperatorSubscriber(subscriber, endDuration, cleanupDuration))
- );
- }
- },
- () => {
- isComplete = true;
- (!hasValue || !durationSubscriber || durationSubscriber.closed) && subscriber.complete();
- }
- )
- );
- });
- }
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