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- import { Operator } from '../Operator';
- import { Subscriber } from '../Subscriber';
- import { Observable } from '../Observable';
- import { Subscription } from '../Subscription';
- import { OuterSubscriber } from '../OuterSubscriber';
- import { InnerSubscriber } from '../InnerSubscriber';
- import { subscribeToResult } from '../util/subscribeToResult';
- import { OperatorFunction } from '../types';
-
- /**
- * Buffers the source Observable values, using a factory function of closing
- * Observables to determine when to close, emit, and reset the buffer.
- *
- * <span class="informal">Collects values from the past as an array. When it
- * starts collecting values, it calls a function that returns an Observable that
- * tells when to close the buffer and restart collecting.</span>
- *
- * ![](bufferWhen.png)
- *
- * Opens a buffer immediately, then closes the buffer when the observable
- * returned by calling `closingSelector` function emits a value. When it closes
- * the buffer, it immediately opens a new buffer and repeats the process.
- *
- * ## Example
- *
- * Emit an array of the last clicks every [1-5] random seconds
- *
- * ```ts
- * import { fromEvent, interval } from 'rxjs';
- * import { bufferWhen } from 'rxjs/operators';
- *
- * const clicks = fromEvent(document, 'click');
- * const buffered = clicks.pipe(bufferWhen(() =>
- * interval(1000 + Math.random() * 4000)
- * ));
- * buffered.subscribe(x => console.log(x));
- * ```
- *
- *
- * @see {@link buffer}
- * @see {@link bufferCount}
- * @see {@link bufferTime}
- * @see {@link bufferToggle}
- * @see {@link windowWhen}
- *
- * @param {function(): Observable} closingSelector A function that takes no
- * arguments and returns an Observable that signals buffer closure.
- * @return {Observable<T[]>} An observable of arrays of buffered values.
- * @method bufferWhen
- * @owner Observable
- */
- export function bufferWhen<T>(closingSelector: () => Observable<any>): OperatorFunction<T, T[]> {
- return function (source: Observable<T>) {
- return source.lift(new BufferWhenOperator(closingSelector));
- };
- }
-
- class BufferWhenOperator<T> implements Operator<T, T[]> {
-
- constructor(private closingSelector: () => Observable<any>) {
- }
-
- call(subscriber: Subscriber<T[]>, source: any): any {
- return source.subscribe(new BufferWhenSubscriber(subscriber, this.closingSelector));
- }
- }
-
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
- class BufferWhenSubscriber<T> extends OuterSubscriber<T, any> {
- private buffer: T[];
- private subscribing: boolean = false;
- private closingSubscription: Subscription;
-
- constructor(destination: Subscriber<T[]>, private closingSelector: () => Observable<any>) {
- super(destination);
- this.openBuffer();
- }
-
- protected _next(value: T) {
- this.buffer.push(value);
- }
-
- protected _complete() {
- const buffer = this.buffer;
- if (buffer) {
- this.destination.next(buffer);
- }
- super._complete();
- }
-
- /** @deprecated This is an internal implementation detail, do not use. */
- _unsubscribe() {
- this.buffer = null;
- this.subscribing = false;
- }
-
- notifyNext(outerValue: T, innerValue: any,
- outerIndex: number, innerIndex: number,
- innerSub: InnerSubscriber<T, any>): void {
- this.openBuffer();
- }
-
- notifyComplete(): void {
- if (this.subscribing) {
- this.complete();
- } else {
- this.openBuffer();
- }
- }
-
- openBuffer() {
- let { closingSubscription } = this;
-
- if (closingSubscription) {
- this.remove(closingSubscription);
- closingSubscription.unsubscribe();
- }
-
- const buffer = this.buffer;
- if (this.buffer) {
- this.destination.next(buffer);
- }
-
- this.buffer = [];
-
- let closingNotifier;
- try {
- const { closingSelector } = this;
- closingNotifier = closingSelector();
- } catch (err) {
- return this.error(err);
- }
- closingSubscription = new Subscription();
- this.closingSubscription = closingSubscription;
- this.add(closingSubscription);
- this.subscribing = true;
- closingSubscription.add(subscribeToResult(this, closingNotifier));
- this.subscribing = false;
- }
- }
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