es6/operators/windowToggle.js

import { Subject } from '../Subject';
import { Subscription } from '../Subscription';
import { tryCatch } from '../util/tryCatch';
import { errorObject } from '../util/errorObject';
import { OuterSubscriber } from '../OuterSubscriber';
import { subscribeToResult } from '../util/subscribeToResult';
/**
 * Branch out the source Observable values as a nested Observable starting from
 * an emission from `openings` and ending when the output of `closingSelector`
 * emits.
 *
 * <span class="informal">It's like {@link bufferToggle}, but emits a nested
 * Observable instead of an array.</span>
 *
 * <img src="./img/windowToggle.png" width="100%">
 *
 * Returns an Observable that emits windows of items it collects from the source
 * Observable. The output Observable emits windows that contain those items
 * emitted by the source Observable between the time when the `openings`
 * Observable emits an item and when the Observable returned by
 * `closingSelector` emits an item.
 *
 * @example <caption>Every other second, emit the click events from the next 500ms</caption>
 * var clicks = Rx.Observable.fromEvent(document, 'click');
 * var openings = Rx.Observable.interval(1000);
 * var result = clicks.windowToggle(openings, i =>
 *   i % 2 ? Rx.Observable.interval(500) : Rx.Observable.empty()
 * ).mergeAll();
 * result.subscribe(x => console.log(x));
 *
 * @see {@link window}
 * @see {@link windowCount}
 * @see {@link windowTime}
 * @see {@link windowWhen}
 * @see {@link bufferToggle}
 *
 * @param {Observable<O>} openings An observable of notifications to start new
 * windows.
 * @param {function(value: O): Observable} closingSelector A function that takes
 * the value emitted by the `openings` observable and returns an Observable,
 * which, when it emits (either `next` or `complete`), signals that the
 * associated window should complete.
 * @return {Observable<Observable<T>>} An observable of windows, which in turn
 * are Observables.
 * @method windowToggle
 * @owner Observable
 */
export function windowToggle(openings, closingSelector) {
    return (source) => source.lift(new WindowToggleOperator(openings, closingSelector));
}
class WindowToggleOperator {
    constructor(openings, closingSelector) {
        this.openings = openings;
        this.closingSelector = closingSelector;
    }
    call(subscriber, source) {
        return source.subscribe(new WindowToggleSubscriber(subscriber, this.openings, this.closingSelector));
    }
}
/**
 * We need this JSDoc comment for affecting ESDoc.
 * @ignore
 * @extends {Ignored}
 */
class WindowToggleSubscriber extends OuterSubscriber {
    constructor(destination, openings, closingSelector) {
        super(destination);
        this.openings = openings;
        this.closingSelector = closingSelector;
        this.contexts = [];
        this.add(this.openSubscription = subscribeToResult(this, openings, openings));
    }
    _next(value) {
        const { contexts } = this;
        if (contexts) {
            const len = contexts.length;
            for (let i = 0; i < len; i++) {
                contexts[i].window.next(value);
            }
        }
    }
    _error(err) {
        const { contexts } = this;
        this.contexts = null;
        if (contexts) {
            const len = contexts.length;
            let index = -1;
            while (++index < len) {
                const context = contexts[index];
                context.window.error(err);
                context.subscription.unsubscribe();
            }
        }
        super._error(err);
    }
    _complete() {
        const { contexts } = this;
        this.contexts = null;
        if (contexts) {
            const len = contexts.length;
            let index = -1;
            while (++index < len) {
                const context = contexts[index];
                context.window.complete();
                context.subscription.unsubscribe();
            }
        }
        super._complete();
    }
    _unsubscribe() {
        const { contexts } = this;
        this.contexts = null;
        if (contexts) {
            const len = contexts.length;
            let index = -1;
            while (++index < len) {
                const context = contexts[index];
                context.window.unsubscribe();
                context.subscription.unsubscribe();
            }
        }
    }
    notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) {
        if (outerValue === this.openings) {
            const { closingSelector } = this;
            const closingNotifier = tryCatch(closingSelector)(innerValue);
            if (closingNotifier === errorObject) {
                return this.error(errorObject.e);
            }
            else {
                const window = new Subject();
                const subscription = new Subscription();
                const context = { window, subscription };
                this.contexts.push(context);
                const innerSubscription = subscribeToResult(this, closingNotifier, context);
                if (innerSubscription.closed) {
                    this.closeWindow(this.contexts.length - 1);
                }
                else {
                    innerSubscription.context = context;
                    subscription.add(innerSubscription);
                }
                this.destination.next(window);
            }
        }
        else {
            this.closeWindow(this.contexts.indexOf(outerValue));
        }
    }
    notifyError(err) {
        this.error(err);
    }
    notifyComplete(inner) {
        if (inner !== this.openSubscription) {
            this.closeWindow(this.contexts.indexOf(inner.context));
        }
    }
    closeWindow(index) {
        if (index === -1) {
            return;
        }
        const { contexts } = this;
        const context = contexts[index];
        const { window, subscription } = context;
        contexts.splice(index, 1);
        window.complete();
        subscription.unsubscribe();
    }
}
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