throttle.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 a value from the source Observable, then ignores subsequent source
* values for a duration determined by another Observable, then repeats this
* process.
*
* <span class="informal">It's like {@link throttleTime}, but the silencing
* duration is determined by a second Observable.</span>
*
* <img src="./img/throttle.png" width="100%">
*
* `throttle` emits the source Observable values on the output Observable
* when its internal timer is disabled, and ignores source values when the timer
* is enabled. Initially, the timer is disabled. As soon as the first source
* value arrives, it is forwarded to the output Observable, and then the timer
* is enabled by calling the `durationSelector` function with the source value,
* which returns the "duration" Observable. When the duration Observable emits a
* value or completes, the timer is disabled, and this process repeats for the
* next source value.
*
* @example <caption>Emit clicks at a rate of at most one click per second</caption>
* var clicks = Rx.Observable.fromEvent(document, 'click');
* var result = clicks.throttle(ev => Rx.Observable.interval(1000));
* result.subscribe(x => console.log(x));
*
* @see {@link audit}
* @see {@link debounce}
* @see {@link delayWhen}
* @see {@link sample}
* @see {@link throttleTime}
*
* @param {function(value: T): Observable|Promise} durationSelector A function
* that receives a value from the source Observable, for computing the silencing
* duration for each source value, returned as an Observable or a Promise.
* @return {Observable<T>} An Observable that performs the throttle operation to
* limit the rate of emissions from the source.
* @method throttle
* @owner Observable
*/
function throttle(durationSelector) {
return this.lift(new ThrottleOperator(durationSelector));
}
exports.throttle = throttle;
var ThrottleOperator = (function () {
function ThrottleOperator(durationSelector) {
this.durationSelector = durationSelector;
}
ThrottleOperator.prototype.call = function (subscriber, source) {
return source.subscribe(new ThrottleSubscriber(subscriber, this.durationSelector));
};
return ThrottleOperator;
}());
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var ThrottleSubscriber = (function (_super) {
__extends(ThrottleSubscriber, _super);
function ThrottleSubscriber(destination, durationSelector) {
_super.call(this, destination);
this.destination = destination;
this.durationSelector = durationSelector;
}
ThrottleSubscriber.prototype._next = function (value) {
if (!this.throttled) {
this.tryDurationSelector(value);
}
};
ThrottleSubscriber.prototype.tryDurationSelector = function (value) {
var duration = null;
try {
duration = this.durationSelector(value);
}
catch (err) {
this.destination.error(err);
return;
}
this.emitAndThrottle(value, duration);
};
ThrottleSubscriber.prototype.emitAndThrottle = function (value, duration) {
this.add(this.throttled = subscribeToResult_1.subscribeToResult(this, duration));
this.destination.next(value);
};
ThrottleSubscriber.prototype._unsubscribe = function () {
var throttled = this.throttled;
if (throttled) {
this.remove(throttled);
this.throttled = null;
throttled.unsubscribe();
}
};
ThrottleSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) {
this._unsubscribe();
};
ThrottleSubscriber.prototype.notifyComplete = function () {
this._unsubscribe();
};
return ThrottleSubscriber;
}(OuterSubscriber_1.OuterSubscriber));
//# sourceMappingURL=throttle.js.map