work.suroh.tk/node_modules/rxjs/_esm2015/operators/windowCount.js

122 lines
4.6 KiB
JavaScript

import { Subscriber } from '../Subscriber';
import { Subject } from '../Subject';
/**
* Branch out the source Observable values as a nested Observable with each
* nested Observable emitting at most `windowSize` values.
*
* <span class="informal">It's like {@link bufferCount}, but emits a nested
* Observable instead of an array.</span>
*
* <img src="./img/windowCount.png" width="100%">
*
* Returns an Observable that emits windows of items it collects from the source
* Observable. The output Observable emits windows every `startWindowEvery`
* items, each containing no more than `windowSize` items. When the source
* Observable completes or encounters an error, the output Observable emits
* the current window and propagates the notification from the source
* Observable. If `startWindowEvery` is not provided, then new windows are
* started immediately at the start of the source and when each window completes
* with size `windowSize`.
*
* @example <caption>Ignore every 3rd click event, starting from the first one</caption>
* var clicks = Rx.Observable.fromEvent(document, 'click');
* var result = clicks.windowCount(3)
* .map(win => win.skip(1)) // skip first of every 3 clicks
* .mergeAll(); // flatten the Observable-of-Observables
* result.subscribe(x => console.log(x));
*
* @example <caption>Ignore every 3rd click event, starting from the third one</caption>
* var clicks = Rx.Observable.fromEvent(document, 'click');
* var result = clicks.windowCount(2, 3)
* .mergeAll(); // flatten the Observable-of-Observables
* result.subscribe(x => console.log(x));
*
* @see {@link window}
* @see {@link windowTime}
* @see {@link windowToggle}
* @see {@link windowWhen}
* @see {@link bufferCount}
*
* @param {number} windowSize The maximum number of values emitted by each
* window.
* @param {number} [startWindowEvery] Interval at which to start a new window.
* For example if `startWindowEvery` is `2`, then a new window will be started
* on every other value from the source. A new window is started at the
* beginning of the source by default.
* @return {Observable<Observable<T>>} An Observable of windows, which in turn
* are Observable of values.
* @method windowCount
* @owner Observable
*/
export function windowCount(windowSize, startWindowEvery = 0) {
return function windowCountOperatorFunction(source) {
return source.lift(new WindowCountOperator(windowSize, startWindowEvery));
};
}
class WindowCountOperator {
constructor(windowSize, startWindowEvery) {
this.windowSize = windowSize;
this.startWindowEvery = startWindowEvery;
}
call(subscriber, source) {
return source.subscribe(new WindowCountSubscriber(subscriber, this.windowSize, this.startWindowEvery));
}
}
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
class WindowCountSubscriber extends Subscriber {
constructor(destination, windowSize, startWindowEvery) {
super(destination);
this.destination = destination;
this.windowSize = windowSize;
this.startWindowEvery = startWindowEvery;
this.windows = [new Subject()];
this.count = 0;
destination.next(this.windows[0]);
}
_next(value) {
const startWindowEvery = (this.startWindowEvery > 0) ? this.startWindowEvery : this.windowSize;
const destination = this.destination;
const windowSize = this.windowSize;
const windows = this.windows;
const len = windows.length;
for (let i = 0; i < len && !this.closed; i++) {
windows[i].next(value);
}
const c = this.count - windowSize + 1;
if (c >= 0 && c % startWindowEvery === 0 && !this.closed) {
windows.shift().complete();
}
if (++this.count % startWindowEvery === 0 && !this.closed) {
const window = new Subject();
windows.push(window);
destination.next(window);
}
}
_error(err) {
const windows = this.windows;
if (windows) {
while (windows.length > 0 && !this.closed) {
windows.shift().error(err);
}
}
this.destination.error(err);
}
_complete() {
const windows = this.windows;
if (windows) {
while (windows.length > 0 && !this.closed) {
windows.shift().complete();
}
}
this.destination.complete();
}
/** @deprecated internal use only */ _unsubscribe() {
this.count = 0;
this.windows = null;
}
}
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