102 lines
3.4 KiB
JavaScript
102 lines
3.4 KiB
JavaScript
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import { Subject } from '../Subject';
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import { OuterSubscriber } from '../OuterSubscriber';
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import { subscribeToResult } from '../util/subscribeToResult';
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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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* <img src="./img/window.png" width="100%">
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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 <caption>In every window of 1 second each, emit at most 2 click events</caption>
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* var clicks = Rx.Observable.fromEvent(document, 'click');
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* var interval = Rx.Observable.interval(1000);
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* var result = clicks.window(interval)
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* .map(win => win.take(2)) // each window has at most 2 emissions
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* .mergeAll(); // flatten the Observable-of-Observables
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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(windowBoundaries) {
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return function windowOperatorFunction(source) {
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return source.lift(new WindowOperator(windowBoundaries));
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};
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}
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class WindowOperator {
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constructor(windowBoundaries) {
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this.windowBoundaries = windowBoundaries;
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}
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call(subscriber, source) {
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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(subscribeToResult(windowSubscriber, this.windowBoundaries));
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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 extends OuterSubscriber {
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constructor(destination) {
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super(destination);
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this.window = new Subject();
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destination.next(this.window);
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}
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notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) {
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this.openWindow();
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}
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notifyError(error, innerSub) {
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this._error(error);
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}
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notifyComplete(innerSub) {
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this._complete();
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}
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_next(value) {
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this.window.next(value);
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}
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_error(err) {
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this.window.error(err);
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this.destination.error(err);
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}
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_complete() {
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this.window.complete();
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this.destination.complete();
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}
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/** @deprecated internal use only */ _unsubscribe() {
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this.window = null;
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}
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openWindow() {
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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();
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destination.next(newWindow);
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}
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}
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//# sourceMappingURL=window.js.map
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