biobulkbende.org/node_modules/rxjs/_esm2015/operators/window.js
2020-09-16 14:23:28 +02:00

102 lines
3.4 KiB
JavaScript

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