blob: dd764e660ef59c2d8a2b5cc0b7079b6de2f9d7a0 [file] [log] [blame]
import { OperatorFunction } from '../types';
/**
* Buffers the source Observable values until the size hits the maximum
* `bufferSize` given.
*
* <span class="informal">Collects values from the past as an array, and emits
* that array only when its size reaches `bufferSize`.</span>
*
* ![](bufferCount.png)
*
* Buffers a number of values from the source Observable by `bufferSize` then
* emits the buffer and clears it, and starts a new buffer each
* `startBufferEvery` values. If `startBufferEvery` is not provided or is
* `null`, then new buffers are started immediately at the start of the source
* and when each buffer closes and is emitted.
*
* ## Examples
*
* Emit the last two click events as an array
*
* ```ts
* import { fromEvent } from 'rxjs';
* import { bufferCount } from 'rxjs/operators';
*
* const clicks = fromEvent(document, 'click');
* const buffered = clicks.pipe(bufferCount(2));
* buffered.subscribe(x => console.log(x));
* ```
*
* On every click, emit the last two click events as an array
*
* ```ts
* import { fromEvent } from 'rxjs';
* import { bufferCount } from 'rxjs/operators';
*
* const clicks = fromEvent(document, 'click');
* const buffered = clicks.pipe(bufferCount(2, 1));
* buffered.subscribe(x => console.log(x));
* ```
*
* @see {@link buffer}
* @see {@link bufferTime}
* @see {@link bufferToggle}
* @see {@link bufferWhen}
* @see {@link pairwise}
* @see {@link windowCount}
*
* @param {number} bufferSize The maximum size of the buffer emitted.
* @param {number} [startBufferEvery] Interval at which to start a new buffer.
* For example if `startBufferEvery` is `2`, then a new buffer will be started
* on every other value from the source. A new buffer is started at the
* beginning of the source by default.
* @return {Observable<T[]>} An Observable of arrays of buffered values.
* @method bufferCount
* @owner Observable
*/
export declare function bufferCount<T>(bufferSize: number, startBufferEvery?: number): OperatorFunction<T, T[]>;