| import { Observable } from '../Observable'; |
| import { OperatorFunction } from '../types'; |
| import { Subject } from '../Subject'; |
| import { Subscriber } from '../Subscriber'; |
| import { OuterSubscriber } from '../OuterSubscriber'; |
| import { InnerSubscriber } from '../InnerSubscriber'; |
| import { subscribeToResult } from '../util/subscribeToResult'; |
| import { Operator } from '../Operator'; |
| |
| /** |
| * Branch out the source Observable values as a nested Observable whenever |
| * `windowBoundaries` emits. |
| * |
| * <span class="informal">It's like {@link buffer}, but emits a nested Observable |
| * instead of an array.</span> |
| * |
| * ![](window.png) |
| * |
| * Returns an Observable that emits windows of items it collects from the source |
| * Observable. The output Observable emits connected, non-overlapping |
| * windows. It emits the current window and opens a new one whenever the |
| * Observable `windowBoundaries` emits an item. Because each window is an |
| * Observable, the output is a higher-order Observable. |
| * |
| * ## Example |
| * In every window of 1 second each, emit at most 2 click events |
| * ```ts |
| * import { fromEvent, interval } from 'rxjs'; |
| * import { window, mergeAll, map, take } from 'rxjs/operators'; |
| * |
| * const clicks = fromEvent(document, 'click'); |
| * const sec = interval(1000); |
| * const result = clicks.pipe( |
| * window(sec), |
| * map(win => win.pipe(take(2))), // each window has at most 2 emissions |
| * mergeAll(), // flatten the Observable-of-Observables |
| * ); |
| * result.subscribe(x => console.log(x)); |
| * ``` |
| * @see {@link windowCount} |
| * @see {@link windowTime} |
| * @see {@link windowToggle} |
| * @see {@link windowWhen} |
| * @see {@link buffer} |
| * |
| * @param {Observable<any>} windowBoundaries An Observable that completes the |
| * previous window and starts a new window. |
| * @return {Observable<Observable<T>>} An Observable of windows, which are |
| * Observables emitting values of the source Observable. |
| * @method window |
| * @owner Observable |
| */ |
| export function window<T>(windowBoundaries: Observable<any>): OperatorFunction<T, Observable<T>> { |
| return function windowOperatorFunction(source: Observable<T>) { |
| return source.lift(new WindowOperator(windowBoundaries)); |
| }; |
| } |
| |
| class WindowOperator<T> implements Operator<T, Observable<T>> { |
| |
| constructor(private windowBoundaries: Observable<any>) { |
| } |
| |
| call(subscriber: Subscriber<Observable<T>>, source: any): any { |
| const windowSubscriber = new WindowSubscriber(subscriber); |
| const sourceSubscription = source.subscribe(windowSubscriber); |
| if (!sourceSubscription.closed) { |
| windowSubscriber.add(subscribeToResult(windowSubscriber, this.windowBoundaries)); |
| } |
| return sourceSubscription; |
| } |
| } |
| |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class WindowSubscriber<T> extends OuterSubscriber<T, any> { |
| |
| private window: Subject<T> = new Subject<T>(); |
| |
| constructor(destination: Subscriber<Observable<T>>) { |
| super(destination); |
| destination.next(this.window); |
| } |
| |
| notifyNext(outerValue: T, innerValue: any, |
| outerIndex: number, innerIndex: number, |
| innerSub: InnerSubscriber<T, any>): void { |
| this.openWindow(); |
| } |
| |
| notifyError(error: any, innerSub: InnerSubscriber<T, any>): void { |
| this._error(error); |
| } |
| |
| notifyComplete(innerSub: InnerSubscriber<T, any>): void { |
| this._complete(); |
| } |
| |
| protected _next(value: T): void { |
| this.window.next(value); |
| } |
| |
| protected _error(err: any): void { |
| this.window.error(err); |
| this.destination.error(err); |
| } |
| |
| protected _complete(): void { |
| this.window.complete(); |
| this.destination.complete(); |
| } |
| |
| /** @deprecated This is an internal implementation detail, do not use. */ |
| _unsubscribe() { |
| this.window = null; |
| } |
| |
| private openWindow(): void { |
| const prevWindow = this.window; |
| if (prevWindow) { |
| prevWindow.complete(); |
| } |
| const destination = this.destination; |
| const newWindow = this.window = new Subject<T>(); |
| destination.next(newWindow); |
| } |
| } |