sample.js
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"use strict";
var __extends = (this && this.__extends) || function (d, b) {
for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
var OuterSubscriber_1 = require('../OuterSubscriber');
var subscribeToResult_1 = require('../util/subscribeToResult');
/**
* Emits the most recently emitted value from the source Observable whenever
* another Observable, the `notifier`, emits.
*
* <span class="informal">It's like {@link sampleTime}, but samples whenever
* the `notifier` Observable emits something.</span>
*
* <img src="./img/sample.png" width="100%">
*
* Whenever the `notifier` Observable emits a value or completes, `sample`
* looks at the source Observable and emits whichever value it has most recently
* emitted since the previous sampling, unless the source has not emitted
* anything since the previous sampling. The `notifier` is subscribed to as soon
* as the output Observable is subscribed.
*
* @example <caption>On every click, sample the most recent "seconds" timer</caption>
* var seconds = Rx.Observable.interval(1000);
* var clicks = Rx.Observable.fromEvent(document, 'click');
* var result = seconds.sample(clicks);
* result.subscribe(x => console.log(x));
*
* @see {@link audit}
* @see {@link debounce}
* @see {@link sampleTime}
* @see {@link throttle}
*
* @param {Observable<any>} notifier The Observable to use for sampling the
* source Observable.
* @return {Observable<T>} An Observable that emits the results of sampling the
* values emitted by the source Observable whenever the notifier Observable
* emits value or completes.
* @method sample
* @owner Observable
*/
function sample(notifier) {
return this.lift(new SampleOperator(notifier));
}
exports.sample = sample;
var SampleOperator = (function () {
function SampleOperator(notifier) {
this.notifier = notifier;
}
SampleOperator.prototype.call = function (subscriber, source) {
var sampleSubscriber = new SampleSubscriber(subscriber);
var subscription = source.subscribe(sampleSubscriber);
subscription.add(subscribeToResult_1.subscribeToResult(sampleSubscriber, this.notifier));
return subscription;
};
return SampleOperator;
}());
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var SampleSubscriber = (function (_super) {
__extends(SampleSubscriber, _super);
function SampleSubscriber() {
_super.apply(this, arguments);
this.hasValue = false;
}
SampleSubscriber.prototype._next = function (value) {
this.value = value;
this.hasValue = true;
};
SampleSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) {
this.emitValue();
};
SampleSubscriber.prototype.notifyComplete = function () {
this.emitValue();
};
SampleSubscriber.prototype.emitValue = function () {
if (this.hasValue) {
this.hasValue = false;
this.destination.next(this.value);
}
};
return SampleSubscriber;
}(OuterSubscriber_1.OuterSubscriber));
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