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