import { Operator } from '../Operator';
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import { Observable } from '../Observable';
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import { Subscriber } from '../Subscriber';
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import { Subscription } from '../Subscription';
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import { ObservableInput, OperatorFunction, ObservedValueOf } from '../types';
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import { map } from './map';
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import { from } from '../observable/from';
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import { SimpleOuterSubscriber, SimpleInnerSubscriber, innerSubscribe } from '../innerSubscribe';
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/* tslint:disable:max-line-length */
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export function exhaustMap<T, O extends ObservableInput<any>>(project: (value: T, index: number) => O): OperatorFunction<T, ObservedValueOf<O>>;
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/** @deprecated resultSelector is no longer supported. Use inner map instead. */
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export function exhaustMap<T, O extends ObservableInput<any>>(project: (value: T, index: number) => O, resultSelector: undefined): OperatorFunction<T, ObservedValueOf<O>>;
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/** @deprecated resultSelector is no longer supported. Use inner map instead. */
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export function exhaustMap<T, I, R>(project: (value: T, index: number) => ObservableInput<I>, resultSelector: (outerValue: T, innerValue: I, outerIndex: number, innerIndex: number) => R): OperatorFunction<T, R>;
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/* tslint:enable:max-line-length */
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/**
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* Projects each source value to an Observable which is merged in the output
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* Observable only if the previous projected Observable has completed.
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*
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* <span class="informal">Maps each value to an Observable, then flattens all of
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* these inner Observables using {@link exhaust}.</span>
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*
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* 
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*
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* Returns an Observable that emits items based on applying a function that you
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* supply to each item emitted by the source Observable, where that function
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* returns an (so-called "inner") Observable. When it projects a source value to
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* an Observable, the output Observable begins emitting the items emitted by
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* that projected Observable. However, `exhaustMap` ignores every new projected
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* Observable if the previous projected Observable has not yet completed. Once
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* that one completes, it will accept and flatten the next projected Observable
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* and repeat this process.
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*
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* ## Example
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* Run a finite timer for each click, only if there is no currently active timer
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* ```ts
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* import { fromEvent, interval } from 'rxjs';
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* import { exhaustMap, take } from 'rxjs/operators';
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*
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* const clicks = fromEvent(document, 'click');
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* const result = clicks.pipe(
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* exhaustMap(ev => interval(1000).pipe(take(5)))
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* );
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* result.subscribe(x => console.log(x));
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* ```
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*
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* @see {@link concatMap}
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* @see {@link exhaust}
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* @see {@link mergeMap}
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* @see {@link switchMap}
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*
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* @param {function(value: T, ?index: number): ObservableInput} project A function
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* that, when applied to an item emitted by the source Observable, returns an
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* Observable.
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* @return {Observable} An Observable containing projected Observables
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* of each item of the source, ignoring projected Observables that start before
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* their preceding Observable has completed.
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* @method exhaustMap
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* @owner Observable
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*/
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export function exhaustMap<T, R, O extends ObservableInput<any>>(
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project: (value: T, index: number) => O,
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resultSelector?: (outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R,
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): OperatorFunction<T, ObservedValueOf<O>|R> {
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if (resultSelector) {
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// DEPRECATED PATH
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return (source: Observable<T>) => source.pipe(
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exhaustMap((a, i) => from(project(a, i)).pipe(
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map((b: any, ii: any) => resultSelector(a, b, i, ii)),
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)),
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);
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}
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return (source: Observable<T>) =>
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source.lift(new ExhaustMapOperator(project));
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}
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class ExhaustMapOperator<T, R> implements Operator<T, R> {
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constructor(private project: (value: T, index: number) => ObservableInput<R>) {
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}
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call(subscriber: Subscriber<R>, source: any): any {
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return source.subscribe(new ExhaustMapSubscriber(subscriber, this.project));
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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 ExhaustMapSubscriber<T, R> extends SimpleOuterSubscriber<T, R> {
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private hasSubscription = false;
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private hasCompleted = false;
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private index = 0;
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constructor(destination: Subscriber<R>,
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private project: (value: T, index: number) => ObservableInput<R>) {
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super(destination);
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}
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protected _next(value: T): void {
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if (!this.hasSubscription) {
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this.tryNext(value);
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}
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}
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private tryNext(value: T): void {
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let result: ObservableInput<R>;
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const index = this.index++;
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try {
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result = this.project(value, index);
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} catch (err) {
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this.destination.error!(err);
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return;
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}
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this.hasSubscription = true;
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this._innerSub(result);
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}
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private _innerSub(result: ObservableInput<R>): void {
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const innerSubscriber = new SimpleInnerSubscriber(this);
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const destination = this.destination as Subscription;
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destination.add(innerSubscriber);
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const innerSubscription = innerSubscribe(result, innerSubscriber);
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// The returned subscription will usually be the subscriber that was
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// passed. However, interop subscribers will be wrapped and for
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// unsubscriptions to chain correctly, the wrapper needs to be added, too.
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if (innerSubscription !== innerSubscriber) {
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destination.add(innerSubscription);
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}
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}
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protected _complete(): void {
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this.hasCompleted = true;
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if (!this.hasSubscription) {
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this.destination.complete!();
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}
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this.unsubscribe();
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}
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notifyNext(innerValue: R): void {
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this.destination.next!(innerValue);
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}
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notifyError(err: any): void {
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this.destination.error!(err);
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}
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notifyComplete(): void {
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this.hasSubscription = false;
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if (this.hasCompleted) {
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this.destination.complete!();
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}
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}
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}
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