114 lines
3.8 KiB
JavaScript
114 lines
3.8 KiB
JavaScript
import { Subscription } from '../Subscription';
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import { tryCatch } from '../util/tryCatch';
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import { errorObject } from '../util/errorObject';
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import { OuterSubscriber } from '../OuterSubscriber';
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import { subscribeToResult } from '../util/subscribeToResult';
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/**
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* Buffers the source Observable values, using a factory function of closing
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* Observables to determine when to close, emit, and reset the buffer.
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*
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* <span class="informal">Collects values from the past as an array. When it
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* starts collecting values, it calls a function that returns an Observable that
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* tells when to close the buffer and restart collecting.</span>
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*
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* <img src="./img/bufferWhen.png" width="100%">
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*
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* Opens a buffer immediately, then closes the buffer when the observable
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* returned by calling `closingSelector` function emits a value. When it closes
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* the buffer, it immediately opens a new buffer and repeats the process.
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*
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* @example <caption>Emit an array of the last clicks every [1-5] random seconds</caption>
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* var clicks = Rx.Observable.fromEvent(document, 'click');
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* var buffered = clicks.bufferWhen(() =>
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* Rx.Observable.interval(1000 + Math.random() * 4000)
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* );
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* buffered.subscribe(x => console.log(x));
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*
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* @see {@link buffer}
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* @see {@link bufferCount}
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* @see {@link bufferTime}
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* @see {@link bufferToggle}
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* @see {@link windowWhen}
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*
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* @param {function(): Observable} closingSelector A function that takes no
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* arguments and returns an Observable that signals buffer closure.
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* @return {Observable<T[]>} An observable of arrays of buffered values.
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* @method bufferWhen
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* @owner Observable
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*/
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export function bufferWhen(closingSelector) {
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return function (source) {
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return source.lift(new BufferWhenOperator(closingSelector));
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};
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}
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class BufferWhenOperator {
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constructor(closingSelector) {
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this.closingSelector = closingSelector;
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}
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call(subscriber, source) {
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return source.subscribe(new BufferWhenSubscriber(subscriber, this.closingSelector));
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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 BufferWhenSubscriber extends OuterSubscriber {
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constructor(destination, closingSelector) {
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super(destination);
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this.closingSelector = closingSelector;
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this.subscribing = false;
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this.openBuffer();
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}
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_next(value) {
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this.buffer.push(value);
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}
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_complete() {
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const buffer = this.buffer;
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if (buffer) {
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this.destination.next(buffer);
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}
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super._complete();
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}
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/** @deprecated internal use only */ _unsubscribe() {
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this.buffer = null;
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this.subscribing = false;
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}
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notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) {
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this.openBuffer();
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}
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notifyComplete() {
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if (this.subscribing) {
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this.complete();
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}
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else {
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this.openBuffer();
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}
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}
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openBuffer() {
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let { closingSubscription } = this;
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if (closingSubscription) {
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this.remove(closingSubscription);
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closingSubscription.unsubscribe();
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}
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const buffer = this.buffer;
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if (this.buffer) {
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this.destination.next(buffer);
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}
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this.buffer = [];
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const closingNotifier = tryCatch(this.closingSelector)();
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if (closingNotifier === errorObject) {
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this.error(errorObject.e);
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}
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else {
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closingSubscription = new Subscription();
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this.closingSubscription = closingSubscription;
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this.add(closingSubscription);
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this.subscribing = true;
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closingSubscription.add(subscribeToResult(this, closingNotifier));
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this.subscribing = false;
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}
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}
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}
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//# sourceMappingURL=bufferWhen.js.map
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