48 lines
1.9 KiB
TypeScript
48 lines
1.9 KiB
TypeScript
import { Observable } from '../Observable';
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import { OperatorFunction } from '../types';
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/**
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* Branch out the source Observable values as a nested Observable using a
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* factory function of closing Observables to determine when to start a new
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* window.
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*
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* <span class="informal">It's like {@link bufferWhen}, but emits a nested
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* Observable instead of an array.</span>
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*
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* ![](windowWhen.png)
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*
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* Returns an Observable that emits windows of items it collects from the source
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* Observable. The output Observable emits connected, non-overlapping windows.
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* It emits the current window and opens a new one whenever the Observable
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* produced by the specified `closingSelector` function emits an item. The first
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* window is opened immediately when subscribing to the output Observable.
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*
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* ## Example
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* Emit only the first two clicks events in every window of [1-5] random seconds
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* ```ts
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* import { fromEvent, interval } from 'rxjs';
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* import { windowWhen, map, mergeAll, 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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* windowWhen(() => interval(1000 + Math.random() * 4000)),
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* map(win => win.pipe(take(2))), // each window has at most 2 emissions
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* mergeAll() // flatten the Observable-of-Observables
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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 window}
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* @see {@link windowCount}
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* @see {@link windowTime}
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* @see {@link windowToggle}
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* @see {@link bufferWhen}
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*
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* @param {function(): Observable} closingSelector A function that takes no
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* arguments and returns an Observable that signals (on either `next` or
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* `complete`) when to close the previous window and start a new one.
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* @return {Observable<Observable<T>>} An observable of windows, which in turn
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* are Observables.
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* @method windowWhen
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* @owner Observable
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*/
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export declare function windowWhen<T>(closingSelector: () => Observable<any>): OperatorFunction<T, Observable<T>>;
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