bufferToggle.js

"use strict";
var __extends = (this && this.__extends) || function (d, b) {
    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
    function __() { this.constructor = d; }
    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
var Subscription_1 = require('../Subscription');
var subscribeToResult_1 = require('../util/subscribeToResult');
var OuterSubscriber_1 = require('../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
 */
function bufferToggle(openings, closingSelector) {
    return function bufferToggleOperatorFunction(source) {
        return source.lift(new BufferToggleOperator(openings, closingSelector));
    };
}
exports.bufferToggle = bufferToggle;
var BufferToggleOperator = (function () {
    function BufferToggleOperator(openings, closingSelector) {
        this.openings = openings;
        this.closingSelector = closingSelector;
    }
    BufferToggleOperator.prototype.call = function (subscriber, source) {
        return source.subscribe(new BufferToggleSubscriber(subscriber, this.openings, this.closingSelector));
    };
    return BufferToggleOperator;
}());
/**
 * We need this JSDoc comment for affecting ESDoc.
 * @ignore
 * @extends {Ignored}
 */
var BufferToggleSubscriber = (function (_super) {
    __extends(BufferToggleSubscriber, _super);
    function BufferToggleSubscriber(destination, openings, closingSelector) {
        _super.call(this, destination);
        this.openings = openings;
        this.closingSelector = closingSelector;
        this.contexts = [];
        this.add(subscribeToResult_1.subscribeToResult(this, openings));
    }
    BufferToggleSubscriber.prototype._next = function (value) {
        var contexts = this.contexts;
        var len = contexts.length;
        for (var i = 0; i < len; i++) {
            contexts[i].buffer.push(value);
        }
    };
    BufferToggleSubscriber.prototype._error = function (err) {
        var contexts = this.contexts;
        while (contexts.length > 0) {
            var context = contexts.shift();
            context.subscription.unsubscribe();
            context.buffer = null;
            context.subscription = null;
        }
        this.contexts = null;
        _super.prototype._error.call(this, err);
    };
    BufferToggleSubscriber.prototype._complete = function () {
        var contexts = this.contexts;
        while (contexts.length > 0) {
            var context = contexts.shift();
            this.destination.next(context.buffer);
            context.subscription.unsubscribe();
            context.buffer = null;
            context.subscription = null;
        }
        this.contexts = null;
        _super.prototype._complete.call(this);
    };
    BufferToggleSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) {
        outerValue ? this.closeBuffer(outerValue) : this.openBuffer(innerValue);
    };
    BufferToggleSubscriber.prototype.notifyComplete = function (innerSub) {
        this.closeBuffer(innerSub.context);
    };
    BufferToggleSubscriber.prototype.openBuffer = function (value) {
        try {
            var closingSelector = this.closingSelector;
            var closingNotifier = closingSelector.call(this, value);
            if (closingNotifier) {
                this.trySubscribe(closingNotifier);
            }
        }
        catch (err) {
            this._error(err);
        }
    };
    BufferToggleSubscriber.prototype.closeBuffer = function (context) {
        var contexts = this.contexts;
        if (contexts && context) {
            var buffer = context.buffer, subscription = context.subscription;
            this.destination.next(buffer);
            contexts.splice(contexts.indexOf(context), 1);
            this.remove(subscription);
            subscription.unsubscribe();
        }
    };
    BufferToggleSubscriber.prototype.trySubscribe = function (closingNotifier) {
        var contexts = this.contexts;
        var buffer = [];
        var subscription = new Subscription_1.Subscription();
        var context = { buffer: buffer, subscription: subscription };
        contexts.push(context);
        var innerSubscription = subscribeToResult_1.subscribeToResult(this, closingNotifier, context);
        if (!innerSubscription || innerSubscription.closed) {
            this.closeBuffer(context);
        }
        else {
            innerSubscription.context = context;
            this.add(innerSubscription);
            subscription.add(innerSubscription);
        }
    };
    return BufferToggleSubscriber;
}(OuterSubscriber_1.OuterSubscriber));
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