| 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; |
| } |
| } |