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