es6/operators/bufferTime.js

import { async } from '../scheduler/async';
import { Subscriber } from '../Subscriber';
import { isScheduler } from '../util/isScheduler';
/* tslint:enable:max-line-length */
/**
 * Buffers the source Observable values for a specific time period.
 *
 * <span class="informal">Collects values from the past as an array, and emits
 * those arrays periodically in time.</span>
 *
 * <img src="./img/bufferTime.png" width="100%">
 *
 * Buffers values from the source for a specific time duration `bufferTimeSpan`.
 * Unless the optional argument `bufferCreationInterval` is given, it emits and
 * resets the buffer every `bufferTimeSpan` milliseconds. If
 * `bufferCreationInterval` is given, this operator opens the buffer every
 * `bufferCreationInterval` milliseconds and closes (emits and resets) the
 * buffer every `bufferTimeSpan` milliseconds. When the optional argument
 * `maxBufferSize` is specified, the buffer will be closed either after
 * `bufferTimeSpan` milliseconds or when it contains `maxBufferSize` elements.
 *
 * @example <caption>Every second, emit an array of the recent click events</caption>
 * var clicks = Rx.Observable.fromEvent(document, 'click');
 * var buffered = clicks.bufferTime(1000);
 * buffered.subscribe(x => console.log(x));
 *
 * @example <caption>Every 5 seconds, emit the click events from the next 2 seconds</caption>
 * var clicks = Rx.Observable.fromEvent(document, 'click');
 * var buffered = clicks.bufferTime(2000, 5000);
 * buffered.subscribe(x => console.log(x));
 *
 * @see {@link buffer}
 * @see {@link bufferCount}
 * @see {@link bufferToggle}
 * @see {@link bufferWhen}
 * @see {@link windowTime}
 *
 * @param {number} bufferTimeSpan The amount of time to fill each buffer array.
 * @param {number} [bufferCreationInterval] The interval at which to start new
 * buffers.
 * @param {number} [maxBufferSize] The maximum buffer size.
 * @param {Scheduler} [scheduler=async] The scheduler on which to schedule the
 * intervals that determine buffer boundaries.
 * @return {Observable<T[]>} An observable of arrays of buffered values.
 * @method bufferTime
 * @owner Observable
 */
export function bufferTime(bufferTimeSpan) {
    let length = arguments.length;
    let scheduler = async;
    if (isScheduler(arguments[arguments.length - 1])) {
        scheduler = arguments[arguments.length - 1];
        length--;
    }
    let bufferCreationInterval = null;
    if (length >= 2) {
        bufferCreationInterval = arguments[1];
    }
    let maxBufferSize = Number.POSITIVE_INFINITY;
    if (length >= 3) {
        maxBufferSize = arguments[2];
    }
    return function bufferTimeOperatorFunction(source) {
        return source.lift(new BufferTimeOperator(bufferTimeSpan, bufferCreationInterval, maxBufferSize, scheduler));
    };
}
class BufferTimeOperator {
    constructor(bufferTimeSpan, bufferCreationInterval, maxBufferSize, scheduler) {
        this.bufferTimeSpan = bufferTimeSpan;
        this.bufferCreationInterval = bufferCreationInterval;
        this.maxBufferSize = maxBufferSize;
        this.scheduler = scheduler;
    }
    call(subscriber, source) {
        return source.subscribe(new BufferTimeSubscriber(subscriber, this.bufferTimeSpan, this.bufferCreationInterval, this.maxBufferSize, this.scheduler));
    }
}
class Context {
    constructor() {
        this.buffer = [];
    }
}
/**
 * We need this JSDoc comment for affecting ESDoc.
 * @ignore
 * @extends {Ignored}
 */
class BufferTimeSubscriber extends Subscriber {
    constructor(destination, bufferTimeSpan, bufferCreationInterval, maxBufferSize, scheduler) {
        super(destination);
        this.bufferTimeSpan = bufferTimeSpan;
        this.bufferCreationInterval = bufferCreationInterval;
        this.maxBufferSize = maxBufferSize;
        this.scheduler = scheduler;
        this.contexts = [];
        const context = this.openContext();
        this.timespanOnly = bufferCreationInterval == null || bufferCreationInterval < 0;
        if (this.timespanOnly) {
            const timeSpanOnlyState = { subscriber: this, context, bufferTimeSpan };
            this.add(context.closeAction = scheduler.schedule(dispatchBufferTimeSpanOnly, bufferTimeSpan, timeSpanOnlyState));
        }
        else {
            const closeState = { subscriber: this, context };
            const creationState = { bufferTimeSpan, bufferCreationInterval, subscriber: this, scheduler };
            this.add(context.closeAction = scheduler.schedule(dispatchBufferClose, bufferTimeSpan, closeState));
            this.add(scheduler.schedule(dispatchBufferCreation, bufferCreationInterval, creationState));
        }
    }
    _next(value) {
        const contexts = this.contexts;
        const len = contexts.length;
        let filledBufferContext;
        for (let i = 0; i < len; i++) {
            const context = contexts[i];
            const buffer = context.buffer;
            buffer.push(value);
            if (buffer.length == this.maxBufferSize) {
                filledBufferContext = context;
            }
        }
        if (filledBufferContext) {
            this.onBufferFull(filledBufferContext);
        }
    }
    _error(err) {
        this.contexts.length = 0;
        super._error(err);
    }
    _complete() {
        const { contexts, destination } = this;
        while (contexts.length > 0) {
            const context = contexts.shift();
            destination.next(context.buffer);
        }
        super._complete();
    }
    _unsubscribe() {
        this.contexts = null;
    }
    onBufferFull(context) {
        this.closeContext(context);
        const closeAction = context.closeAction;
        closeAction.unsubscribe();
        this.remove(closeAction);
        if (!this.closed && this.timespanOnly) {
            context = this.openContext();
            const bufferTimeSpan = this.bufferTimeSpan;
            const timeSpanOnlyState = { subscriber: this, context, bufferTimeSpan };
            this.add(context.closeAction = this.scheduler.schedule(dispatchBufferTimeSpanOnly, bufferTimeSpan, timeSpanOnlyState));
        }
    }
    openContext() {
        const context = new Context();
        this.contexts.push(context);
        return context;
    }
    closeContext(context) {
        this.destination.next(context.buffer);
        const contexts = this.contexts;
        const spliceIndex = contexts ? contexts.indexOf(context) : -1;
        if (spliceIndex >= 0) {
            contexts.splice(contexts.indexOf(context), 1);
        }
    }
}
function dispatchBufferTimeSpanOnly(state) {
    const subscriber = state.subscriber;
    const prevContext = state.context;
    if (prevContext) {
        subscriber.closeContext(prevContext);
    }
    if (!subscriber.closed) {
        state.context = subscriber.openContext();
        state.context.closeAction = this.schedule(state, state.bufferTimeSpan);
    }
}
function dispatchBufferCreation(state) {
    const { bufferCreationInterval, bufferTimeSpan, subscriber, scheduler } = state;
    const context = subscriber.openContext();
    const action = this;
    if (!subscriber.closed) {
        subscriber.add(context.closeAction = scheduler.schedule(dispatchBufferClose, bufferTimeSpan, { subscriber, context }));
        action.schedule(state, bufferCreationInterval);
    }
}
function dispatchBufferClose(arg) {
    const { subscriber, context } = arg;
    subscriber.closeContext(context);
}
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