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- import { Operator } from '../Operator';
- import { Subscriber } from '../Subscriber';
- import { Observable } from '../Observable';
- import { OperatorFunction, TeardownLogic } 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 function bufferCount<T>(bufferSize: number, startBufferEvery: number = null): OperatorFunction<T, T[]> {
- return function bufferCountOperatorFunction(source: Observable<T>) {
- return source.lift(new BufferCountOperator<T>(bufferSize, startBufferEvery));
- };
- }
-
- class BufferCountOperator<T> implements Operator<T, T[]> {
- private subscriberClass: any;
-
- constructor(private bufferSize: number, private startBufferEvery: number) {
- if (!startBufferEvery || bufferSize === startBufferEvery) {
- this.subscriberClass = BufferCountSubscriber;
- } else {
- this.subscriberClass = BufferSkipCountSubscriber;
- }
- }
-
- call(subscriber: Subscriber<T[]>, source: any): TeardownLogic {
- return source.subscribe(new this.subscriberClass(subscriber, this.bufferSize, this.startBufferEvery));
- }
- }
-
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
- class BufferCountSubscriber<T> extends Subscriber<T> {
- private buffer: T[] = [];
-
- constructor(destination: Subscriber<T[]>, private bufferSize: number) {
- super(destination);
- }
-
- protected _next(value: T): void {
- const buffer = this.buffer;
-
- buffer.push(value);
-
- if (buffer.length == this.bufferSize) {
- this.destination.next(buffer);
- this.buffer = [];
- }
- }
-
- protected _complete(): void {
- const buffer = this.buffer;
- if (buffer.length > 0) {
- this.destination.next(buffer);
- }
- super._complete();
- }
- }
-
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
- class BufferSkipCountSubscriber<T> extends Subscriber<T> {
- private buffers: Array<T[]> = [];
- private count: number = 0;
-
- constructor(destination: Subscriber<T[]>, private bufferSize: number, private startBufferEvery: number) {
- super(destination);
- }
-
- protected _next(value: T): void {
- const { bufferSize, startBufferEvery, buffers, count } = this;
-
- this.count++;
- if (count % startBufferEvery === 0) {
- buffers.push([]);
- }
-
- for (let i = buffers.length; i--; ) {
- const buffer = buffers[i];
- buffer.push(value);
- if (buffer.length === bufferSize) {
- buffers.splice(i, 1);
- this.destination.next(buffer);
- }
- }
- }
-
- protected _complete(): void {
- const { buffers, destination } = this;
-
- while (buffers.length > 0) {
- let buffer = buffers.shift();
- if (buffer.length > 0) {
- destination.next(buffer);
- }
- }
- super._complete();
- }
-
- }
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