es6/operators/bufferToggle.js

import { Subscription } from '../Subscription';
import { subscribeToResult } from '../util/subscribeToResult';
import { OuterSubscriber } from '../OuterSubscriber';
/**
 * Buffers the source Observable values starting from an emission from
 * `openings` and ending when the output of `closingSelector` emits.
 *
 * <span class="informal">Collects values from the past as an array. Starts
 * collecting only when `opening` emits, and calls the `closingSelector`
 * function to get an Observable that tells when to close the buffer.</span>
 *
 * <img src="./img/bufferToggle.png" width="100%">
 *
 * Buffers values from the source by opening the buffer via signals from an
 * Observable provided to `openings`, and closing and sending the buffers when
 * a Subscribable or Promise returned by the `closingSelector` function emits.
 *
 * @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 buffered = clicks.bufferToggle(openings, i =>
 *   i % 2 ? Rx.Observable.interval(500) : Rx.Observable.empty()
 * );
 * buffered.subscribe(x => console.log(x));
 *
 * @see {@link buffer}
 * @see {@link bufferCount}
 * @see {@link bufferTime}
 * @see {@link bufferWhen}
 * @see {@link windowToggle}
 *
 * @param {SubscribableOrPromise<O>} openings A Subscribable or Promise of notifications to start new
 * buffers.
 * @param {function(value: O): SubscribableOrPromise} closingSelector A function that takes
 * the value emitted by the `openings` observable and returns a Subscribable or Promise,
 * which, when it emits, signals that the associated buffer should be emitted
 * and cleared.
 * @return {Observable<T[]>} An observable of arrays of buffered values.
 * @method bufferToggle
 * @owner Observable
 */
export function bufferToggle(openings, closingSelector) {
    return function bufferToggleOperatorFunction(source) {
        return source.lift(new BufferToggleOperator(openings, closingSelector));
    };
}
class BufferToggleOperator {
    constructor(openings, closingSelector) {
        this.openings = openings;
        this.closingSelector = closingSelector;
    }
    call(subscriber, source) {
        return source.subscribe(new BufferToggleSubscriber(subscriber, this.openings, this.closingSelector));
    }
}
/**
 * We need this JSDoc comment for affecting ESDoc.
 * @ignore
 * @extends {Ignored}
 */
class BufferToggleSubscriber extends OuterSubscriber {
    constructor(destination, openings, closingSelector) {
        super(destination);
        this.openings = openings;
        this.closingSelector = closingSelector;
        this.contexts = [];
        this.add(subscribeToResult(this, openings));
    }
    _next(value) {
        const contexts = this.contexts;
        const len = contexts.length;
        for (let i = 0; i < len; i++) {
            contexts[i].buffer.push(value);
        }
    }
    _error(err) {
        const contexts = this.contexts;
        while (contexts.length > 0) {
            const context = contexts.shift();
            context.subscription.unsubscribe();
            context.buffer = null;
            context.subscription = null;
        }
        this.contexts = null;
        super._error(err);
    }
    _complete() {
        const contexts = this.contexts;
        while (contexts.length > 0) {
            const context = contexts.shift();
            this.destination.next(context.buffer);
            context.subscription.unsubscribe();
            context.buffer = null;
            context.subscription = null;
        }
        this.contexts = null;
        super._complete();
    }
    notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) {
        outerValue ? this.closeBuffer(outerValue) : this.openBuffer(innerValue);
    }
    notifyComplete(innerSub) {
        this.closeBuffer(innerSub.context);
    }
    openBuffer(value) {
        try {
            const closingSelector = this.closingSelector;
            const closingNotifier = closingSelector.call(this, value);
            if (closingNotifier) {
                this.trySubscribe(closingNotifier);
            }
        }
        catch (err) {
            this._error(err);
        }
    }
    closeBuffer(context) {
        const contexts = this.contexts;
        if (contexts && context) {
            const { buffer, subscription } = context;
            this.destination.next(buffer);
            contexts.splice(contexts.indexOf(context), 1);
            this.remove(subscription);
            subscription.unsubscribe();
        }
    }
    trySubscribe(closingNotifier) {
        const contexts = this.contexts;
        const buffer = [];
        const subscription = new Subscription();
        const context = { buffer, subscription };
        contexts.push(context);
        const innerSubscription = subscribeToResult(this, closingNotifier, context);
        if (!innerSubscription || innerSubscription.closed) {
            this.closeBuffer(context);
        }
        else {
            innerSubscription.context = context;
            this.add(innerSubscription);
            subscription.add(innerSubscription);
        }
    }
}
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