import {OperatorFunction, ObservableInput} from '../types';
|
import { switchMap } from './switchMap';
|
import { identity } from '../util/identity';
|
|
export function switchAll<T>(): OperatorFunction<ObservableInput<T>, T>;
|
export function switchAll<R>(): OperatorFunction<any, R>;
|
|
/**
|
* Converts a higher-order Observable into a first-order Observable
|
* producing values only from the most recent observable sequence
|
*
|
* <span class="informal">Flattens an Observable-of-Observables.</span>
|
*
|
* 
|
*
|
* `switchAll` subscribes to a source that is an observable of observables, also known as a
|
* "higher-order observable" (or `Observable<Observable<T>>`). It subscribes to the most recently
|
* provided "inner observable" emitted by the source, unsubscribing from any previously subscribed
|
* to inner observable, such that only the most recent inner observable may be subscribed to at
|
* any point in time. The resulting observable returned by `switchAll` will only complete if the
|
* source observable completes, *and* any currently subscribed to inner observable also has completed,
|
* if there are any.
|
*
|
* ## Examples
|
* Spawn a new interval observable for each click event, but for every new
|
* click, cancel the previous interval and subscribe to the new one.
|
*
|
* ```ts
|
* import { fromEvent, interval } from 'rxjs';
|
* import { switchAll, map, tap } from 'rxjs/operators';
|
*
|
* const clicks = fromEvent(document, 'click').pipe(tap(() => console.log('click')));
|
* const source = clicks.pipe(map((ev) => interval(1000)));
|
*
|
* source.pipe(
|
* switchAll()
|
* ).subscribe(x => console.log(x));
|
*
|
* // Output
|
* // click
|
* // 1
|
* // 2
|
* // 3
|
* // 4
|
* // ...
|
* // click
|
* // 1
|
* // 2
|
* // 3
|
* // ...
|
* // click
|
* // ...
|
* ```
|
*
|
* @see {@link combineAll}
|
* @see {@link concatAll}
|
* @see {@link exhaust}
|
* @see {@link switchMap}
|
* @see {@link switchMapTo}
|
* @see {@link mergeAll}
|
*/
|
|
export function switchAll<T>(): OperatorFunction<ObservableInput<T>, T> {
|
return switchMap(identity);
|
}
|
