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/RxJS

bufferToggle

function stable

Buffers the source Observable values starting from an emission from openings and ending when the output of closingSelector emits.

`bufferToggle<T, O>(openings: SubscribableOrPromise<O>, closingSelector: (value: O) => SubscribableOrPromise<any>): OperatorFunction<T, T[]>`

Parameters

openings	A Subscribable or Promise of notifications to start new buffers.
closingSelector	A function that takes the value emitted by the `openings` observable and returns a Subscribable or Promise, which, when it emits, signals that the associated buffer should be emitted and cleared.

Returns

OperatorFunction<T, T[]>: An observable of arrays of buffered values.

Description

Collects values from the past as an array. Starts collecting only when opening emits, and calls the closingSelector function to get an Observable that tells when to close the buffer.

bufferToggle marble diagram

Buffers values from the source by opening the buffer via signals from an Observable provided to openings, and closing and sending the buffers when a Subscribable or Promise returned by the closingSelector function emits.

Example

Every other second, emit the click events from the next 500ms

import { fromEvent, interval, EMPTY } from 'rxjs';
import { bufferToggle } from 'rxjs/operators';

const clicks = fromEvent(document, 'click');
const openings = interval(1000);
const buffered = clicks.pipe(bufferToggle(openings, i =>
  i % 2 ? interval(500) : EMPTY
));
buffered.subscribe(x => console.log(x));