+++ /dev/null
-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.png)
- *
- * `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!();
- }
- }
-}