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import { Observable } from '../Observable';
import { Subscriber } from '../Subscriber';
import { ObservableInput, OperatorFunction, ObservedValueOf } from '../types';
import { map } from './map';
import { innerFrom } from '../observable/innerFrom';
import { operate } from '../util/lift';
import { createOperatorSubscriber } from './OperatorSubscriber';
/* tslint:disable:max-line-length */
export function exhaustMap<T, O extends ObservableInput<any>>(
project: (value: T, index: number) => O
): OperatorFunction<T, ObservedValueOf<O>>;
/** @deprecated The `resultSelector` parameter will be removed in v8. Use an inner `map` instead. Details: https://rxjs.dev/deprecations/resultSelector */
export function exhaustMap<T, O extends ObservableInput<any>>(
project: (value: T, index: number) => O,
resultSelector: undefined
): OperatorFunction<T, ObservedValueOf<O>>;
/** @deprecated The `resultSelector` parameter will be removed in v8. Use an inner `map` instead. Details: https://rxjs.dev/deprecations/resultSelector */
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>;
/* tslint:enable:max-line-length */
/**
* Projects each source value to an Observable which is merged in the output
* Observable only if the previous projected Observable has completed.
*
* <span class="informal">Maps each value to an Observable, then flattens all of
* these inner Observables using {@link exhaustAll}.</span>
*
* 
*
* Returns an Observable that emits items based on applying a function that you
* supply to each item emitted by the source Observable, where that function
* returns an (so-called "inner") Observable. When it projects a source value to
* an Observable, the output Observable begins emitting the items emitted by
* that projected Observable. However, `exhaustMap` ignores every new projected
* Observable if the previous projected Observable has not yet completed. Once
* that one completes, it will accept and flatten the next projected Observable
* and repeat this process.
*
* ## Example
*
* Run a finite timer for each click, only if there is no currently active timer
*
* ```ts
* import { fromEvent, exhaustMap, interval, take } from 'rxjs';
*
* const clicks = fromEvent(document, 'click');
* const result = clicks.pipe(
* exhaustMap(() => interval(1000).pipe(take(5)))
* );
* result.subscribe(x => console.log(x));
* ```
*
* @see {@link concatMap}
* @see {@link exhaust}
* @see {@link mergeMap}
* @see {@link switchMap}
*
* @param {function(value: T, ?index: number): ObservableInput} project A function
* that, when applied to an item emitted by the source Observable, returns an
* Observable.
* @return A function that returns an Observable containing projected
* Observables of each item of the source, ignoring projected Observables that
* start before their preceding Observable has completed.
*/
export function exhaustMap<T, R, O extends ObservableInput<any>>(
project: (value: T, index: number) => O,
resultSelector?: (outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R
): OperatorFunction<T, ObservedValueOf<O> | R> {
if (resultSelector) {
// DEPRECATED PATH
return (source: Observable<T>) =>
source.pipe(exhaustMap((a, i) => innerFrom(project(a, i)).pipe(map((b: any, ii: any) => resultSelector(a, b, i, ii)))));
}
return operate((source, subscriber) => {
let index = 0;
let innerSub: Subscriber<T> | null = null;
let isComplete = false;
source.subscribe(
createOperatorSubscriber(
subscriber,
(outerValue) => {
if (!innerSub) {
innerSub = createOperatorSubscriber(subscriber, undefined, () => {
innerSub = null;
isComplete && subscriber.complete();
});
innerFrom(project(outerValue, index++)).subscribe(innerSub);
}
},
() => {
isComplete = true;
!innerSub && subscriber.complete();
}
)
);
});
}