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import { Operator } from '../Operator';
import { Subscriber } from '../Subscriber';
import { Observable } from '../Observable';
import { Subscription } from '../Subscription';
import { MonoTypeOperatorFunction, SubscribableOrPromise, TeardownLogic } from '../types';
import { OuterSubscriber } from '../OuterSubscriber';
import { subscribeToResult } from '../util/subscribeToResult';
/**
* 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 or completes, 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
* ```javascript
* import { fromEvent, interval } from 'rxjs';
* import { audit } from 'rxjs/operators'
*
* 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 {function(value: T): SubscribableOrPromise} durationSelector A function
* that receives a value from the source Observable, for computing the silencing
* duration, returned as an Observable or a Promise.
* @return {Observable<T>} An Observable that performs rate-limiting of
* emissions from the source Observable.
* @method audit
* @owner Observable
*/
export function audit<T>(durationSelector: (value: T) => SubscribableOrPromise<any>): MonoTypeOperatorFunction<T> {
return function auditOperatorFunction(source: Observable<T>) {
return source.lift(new AuditOperator(durationSelector));
};
}
class AuditOperator<T> implements Operator<T, T> {
constructor(private durationSelector: (value: T) => SubscribableOrPromise<any>) {
}
call(subscriber: Subscriber<T>, source: any): TeardownLogic {
return source.subscribe(new AuditSubscriber<T, T>(subscriber, this.durationSelector));
}
}
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
class AuditSubscriber<T, R> extends OuterSubscriber<T, R> {
private value: T;
private hasValue: boolean = false;
private throttled: Subscription;
constructor(destination: Subscriber<T>,
private durationSelector: (value: T) => SubscribableOrPromise<any>) {
super(destination);
}
protected _next(value: T): void {
this.value = value;
this.hasValue = true;
if (!this.throttled) {
let duration;
try {
const { durationSelector } = this;
duration = durationSelector(value);
} catch (err) {
return this.destination.error(err);
}
const innerSubscription = subscribeToResult(this, duration);
if (!innerSubscription || innerSubscription.closed) {
this.clearThrottle();
} else {
this.add(this.throttled = innerSubscription);
}
}
}
clearThrottle() {
const { value, hasValue, throttled } = this;
if (throttled) {
this.remove(throttled);
this.throttled = null;
throttled.unsubscribe();
}
if (hasValue) {
this.value = null;
this.hasValue = false;
this.destination.next(value);
}
}
notifyNext(outerValue: T, innerValue: R, outerIndex: number, innerIndex: number): void {
this.clearThrottle();
}
notifyComplete(): void {
this.clearThrottle();
}
}
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