import { OperatorFunction, ObservableInput, ObservedValueOf } from '../types';
|
import { exhaustMap } from './exhaustMap';
|
import { identity } from '../util/identity';
|
|
/**
|
* 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>
|
*
|
* 
|
*
|
* `exhaustAll` 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,
|
* `exhaustAll` 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, map, interval, take, exhaustAll } from 'rxjs';
|
*
|
* const clicks = fromEvent(document, 'click');
|
* const higherOrder = clicks.pipe(
|
* map(() => interval(1000).pipe(take(5)))
|
* );
|
* const result = higherOrder.pipe(exhaustAll());
|
* result.subscribe(x => console.log(x));
|
* ```
|
*
|
* @see {@link combineLatestAll}
|
* @see {@link concatAll}
|
* @see {@link switchAll}
|
* @see {@link switchMap}
|
* @see {@link mergeAll}
|
* @see {@link exhaustMap}
|
* @see {@link zipAll}
|
*
|
* @return A function that returns an Observable that takes a source of
|
* Observables and propagates the first Observable exclusively until it
|
* completes before subscribing to the next.
|
*/
|
export function exhaustAll<O extends ObservableInput<any>>(): OperatorFunction<O, ObservedValueOf<O>> {
|
return exhaustMap(identity);
|
}
|
