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

190 lines
7.3 KiB
JavaScript

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();
}
/** @deprecated internal use only */ _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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