127 lines
5.1 KiB
JavaScript
127 lines
5.1 KiB
JavaScript
"use strict";
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var __extends = (this && this.__extends) || function (d, b) {
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for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
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function __() { this.constructor = d; }
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d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
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};
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var OuterSubscriber_1 = require('../OuterSubscriber');
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var subscribeToResult_1 = require('../util/subscribeToResult');
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/**
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* Emits a value from the source Observable only after a particular time span
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* determined by another Observable has passed without another source emission.
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*
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* <span class="informal">It's like {@link debounceTime}, but the time span of
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* emission silence is determined by a second Observable.</span>
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*
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* <img src="./img/debounce.png" width="100%">
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*
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* `debounce` delays values emitted by the source Observable, but drops previous
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* pending delayed emissions if a new value arrives on the source Observable.
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* This operator keeps track of the most recent value from the source
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* Observable, and spawns a duration Observable by calling the
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* `durationSelector` function. The value is emitted only when the duration
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* Observable emits a value or completes, and if no other value was emitted on
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* the source Observable since the duration Observable was spawned. If a new
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* value appears before the duration Observable emits, the previous value will
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* be dropped and will not be emitted on the output Observable.
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*
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* Like {@link debounceTime}, this is a rate-limiting operator, and also a
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* delay-like operator since output emissions do not necessarily occur at the
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* same time as they did on the source Observable.
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*
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* @example <caption>Emit the most recent click after a burst of clicks</caption>
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* var clicks = Rx.Observable.fromEvent(document, 'click');
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* var result = clicks.debounce(() => Rx.Observable.interval(1000));
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* result.subscribe(x => console.log(x));
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*
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* @see {@link audit}
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* @see {@link debounceTime}
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* @see {@link delayWhen}
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* @see {@link throttle}
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*
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* @param {function(value: T): SubscribableOrPromise} durationSelector A function
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* that receives a value from the source Observable, for computing the timeout
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* duration for each source value, returned as an Observable or a Promise.
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* @return {Observable} An Observable that delays the emissions of the source
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* Observable by the specified duration Observable returned by
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* `durationSelector`, and may drop some values if they occur too frequently.
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* @method debounce
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* @owner Observable
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*/
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function debounce(durationSelector) {
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return function (source) { return source.lift(new DebounceOperator(durationSelector)); };
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}
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exports.debounce = debounce;
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var DebounceOperator = (function () {
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function DebounceOperator(durationSelector) {
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this.durationSelector = durationSelector;
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}
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DebounceOperator.prototype.call = function (subscriber, source) {
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return source.subscribe(new DebounceSubscriber(subscriber, this.durationSelector));
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};
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return DebounceOperator;
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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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var DebounceSubscriber = (function (_super) {
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__extends(DebounceSubscriber, _super);
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function DebounceSubscriber(destination, durationSelector) {
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_super.call(this, destination);
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this.durationSelector = durationSelector;
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this.hasValue = false;
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this.durationSubscription = null;
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}
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DebounceSubscriber.prototype._next = function (value) {
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try {
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var result = this.durationSelector.call(this, value);
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if (result) {
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this._tryNext(value, result);
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}
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}
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catch (err) {
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this.destination.error(err);
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}
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};
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DebounceSubscriber.prototype._complete = function () {
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this.emitValue();
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this.destination.complete();
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};
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DebounceSubscriber.prototype._tryNext = function (value, duration) {
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var subscription = this.durationSubscription;
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this.value = value;
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this.hasValue = true;
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if (subscription) {
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subscription.unsubscribe();
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this.remove(subscription);
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}
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subscription = subscribeToResult_1.subscribeToResult(this, duration);
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if (!subscription.closed) {
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this.add(this.durationSubscription = subscription);
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}
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};
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DebounceSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) {
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this.emitValue();
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};
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DebounceSubscriber.prototype.notifyComplete = function () {
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this.emitValue();
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};
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DebounceSubscriber.prototype.emitValue = function () {
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if (this.hasValue) {
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var value = this.value;
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var subscription = this.durationSubscription;
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if (subscription) {
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this.durationSubscription = null;
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subscription.unsubscribe();
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this.remove(subscription);
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}
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this.value = null;
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this.hasValue = false;
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_super.prototype._next.call(this, value);
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}
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};
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return DebounceSubscriber;
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}(OuterSubscriber_1.OuterSubscriber));
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//# sourceMappingURL=debounce.js.map
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