window

Branch out the source Observable values as a nested Observable whenever windowBoundaries emits.

window<T>(windowBoundaries: Observable<any>): OperatorFunction<T, Observable<T>>

Parameters

windowBoundaries

Observable<any>

An Observable that completes the previous window and starts a new window.

Returns

OperatorFunction<T, Observable<T>>: A function that returns an Observable of windows, which are Observables emitting values of the source Observable.

Description

It's like buffer, but emits a nested Observable instead of an array.

Returns an Observable that emits windows of items it collects from the source Observable. The output Observable emits connected, non-overlapping windows. It emits the current window and opens a new one whenever the Observable windowBoundaries emits an item. Because each window is an Observable, the output is a higher-order Observable.

Example

In every window of 1 second each, emit at most 2 click events

import { fromEvent, interval, window, map, take, mergeAll } from 'rxjs';

const clicks = fromEvent(document, 'click');
const sec = interval(1000);
const result = clicks.pipe(
  window(sec),
  map(win => win.pipe(take(2))), // take at most 2 emissions from each window
  mergeAll()                     // flatten the Observable-of-Observables
);
result.subscribe(x => console.log(x));

See Also

• windowCount
• windowTime
• windowToggle
• windowWhen
• buffer