Buffers the source Observable values until the size hits the maximum
bufferSize
given.
bufferCount<T>(bufferSize: number, startBufferEvery: number = null): OperatorFunction<T, T[]>
Parameters
bufferSize |
The maximum size of the buffer emitted.
|
startBufferEvery |
Optional. Default is null .
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.
|
Returns
OperatorFunction<T, T[]>
: An Observable of arrays of buffered values.
Description
Collects values from the past as an array, and emits
that array only when its size reaches bufferSize
.

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
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
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));