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import { Operator } from '../Operator';
import { Observable } from '../Observable';
import { Subscriber } from '../Subscriber';
import { ObservableInput, OperatorFunction, TeardownLogic } from '../types';
import { SimpleOuterSubscriber, innerSubscribe, SimpleInnerSubscriber } from '../innerSubscribe';
export function exhaust<T>(): OperatorFunction<ObservableInput<T>, T>;
export function exhaust<R>(): OperatorFunction<any, R>;
/**
* Converts a higher-order Observable into a first-order Observable by dropping
* inner Observables while the previous inner Observable has not yet completed.
*
* <span class="informal">Flattens an Observable-of-Observables by dropping the
* next inner Observables while the current inner is still executing.</span>
*
* 
*
* `exhaust` subscribes to an Observable that emits Observables, also known as a
* higher-order Observable. Each time it observes one of these emitted inner
* Observables, the output Observable begins emitting the items emitted by that
* inner Observable. So far, it behaves like {@link mergeAll}. However,
* `exhaust` ignores every new inner Observable if the previous Observable has
* not yet completed. Once that one completes, it will accept and flatten the
* next inner Observable and repeat this process.
*
* ## Example
* Run a finite timer for each click, only if there is no currently active timer
* ```ts
* import { fromEvent, interval } from 'rxjs';
* import { exhaust, map, take } from 'rxjs/operators';
*
* const clicks = fromEvent(document, 'click');
* const higherOrder = clicks.pipe(
* map((ev) => interval(1000).pipe(take(5))),
* );
* const result = higherOrder.pipe(exhaust());
* result.subscribe(x => console.log(x));
* ```
*
* @see {@link combineAll}
* @see {@link concatAll}
* @see {@link switchAll}
* @see {@link switchMap}
* @see {@link mergeAll}
* @see {@link exhaustMap}
* @see {@link zipAll}
*
* @return {Observable} An Observable that takes a source of Observables and propagates the first observable
* exclusively until it completes before subscribing to the next.
* @method exhaust
* @owner Observable
*/
export function exhaust<T>(): OperatorFunction<any, T> {
return (source: Observable<T>) => source.lift(new SwitchFirstOperator<T>());
}
class SwitchFirstOperator<T> implements Operator<T, T> {
call(subscriber: Subscriber<T>, source: any): TeardownLogic {
return source.subscribe(new SwitchFirstSubscriber(subscriber));
}
}
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
class SwitchFirstSubscriber<T> extends SimpleOuterSubscriber<T, T> {
private hasCompleted: boolean = false;
private hasSubscription: boolean = false;
constructor(destination: Subscriber<T>) {
super(destination);
}
protected _next(value: T): void {
if (!this.hasSubscription) {
this.hasSubscription = true;
this.add(innerSubscribe(value, new SimpleInnerSubscriber(this)));
}
}
protected _complete(): void {
this.hasCompleted = true;
if (!this.hasSubscription) {
this.destination.complete!();
}
}
notifyComplete(): void {
this.hasSubscription = false;
if (this.hasCompleted) {
this.destination.complete!();
}
}
}
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