@reactivex/rxjs
Version:
Reactive Extensions for modern JavaScript
153 lines • 5.86 kB
JavaScript
"use strict";
var __extends = (this && this.__extends) || (function () {
var extendStatics = function (d, b) {
extendStatics = Object.setPrototypeOf ||
({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
return extendStatics(d, b);
}
return function (d, b) {
extendStatics(d, b);
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
})();
Object.defineProperty(exports, "__esModule", { value: true });
var innerSubscribe_1 = require("../innerSubscribe");
exports.defaultThrottleConfig = {
leading: true,
trailing: false
};
/**
* 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>
*
* 
*
* `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
* Emit clicks at a rate of at most one click per second
* ```ts
* import { fromEvent } from 'rxjs';
* import { throttle } from 'rxjs/operators';
*
* const clicks = fromEvent(document, 'click');
* const result = clicks.pipe(throttle(ev => 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): SubscribableOrPromise} 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.
* @param {Object} config a configuration object to define `leading` and `trailing` behavior. Defaults
* to `{ leading: true, trailing: false }`.
* @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, config) {
if (config === void 0) { config = exports.defaultThrottleConfig; }
return function (source) { return source.lift(new ThrottleOperator(durationSelector, !!config.leading, !!config.trailing)); };
}
exports.throttle = throttle;
var ThrottleOperator = /** @class */ (function () {
function ThrottleOperator(durationSelector, leading, trailing) {
this.durationSelector = durationSelector;
this.leading = leading;
this.trailing = trailing;
}
ThrottleOperator.prototype.call = function (subscriber, source) {
return source.subscribe(new ThrottleSubscriber(subscriber, this.durationSelector, this.leading, this.trailing));
};
return ThrottleOperator;
}());
/**
* We need this JSDoc comment for affecting ESDoc
* @ignore
* @extends {Ignored}
*/
var ThrottleSubscriber = /** @class */ (function (_super) {
__extends(ThrottleSubscriber, _super);
function ThrottleSubscriber(destination, durationSelector, _leading, _trailing) {
var _this = _super.call(this, destination) || this;
_this.destination = destination;
_this.durationSelector = durationSelector;
_this._leading = _leading;
_this._trailing = _trailing;
_this._hasValue = false;
return _this;
}
ThrottleSubscriber.prototype._next = function (value) {
this._hasValue = true;
this._sendValue = value;
if (!this._throttled) {
if (this._leading) {
this.send();
}
else {
this.throttle(value);
}
}
};
ThrottleSubscriber.prototype.send = function () {
var _a = this, _hasValue = _a._hasValue, _sendValue = _a._sendValue;
if (_hasValue) {
this.destination.next(_sendValue);
this.throttle(_sendValue);
}
this._hasValue = false;
this._sendValue = undefined;
};
ThrottleSubscriber.prototype.throttle = function (value) {
var duration = this.tryDurationSelector(value);
if (!!duration) {
this.add(this._throttled = innerSubscribe_1.innerSubscribe(duration, new innerSubscribe_1.SimpleInnerSubscriber(this)));
}
};
ThrottleSubscriber.prototype.tryDurationSelector = function (value) {
try {
return this.durationSelector(value);
}
catch (err) {
this.destination.error(err);
return null;
}
};
ThrottleSubscriber.prototype.throttlingDone = function () {
var _a = this, _throttled = _a._throttled, _trailing = _a._trailing;
if (_throttled) {
_throttled.unsubscribe();
}
this._throttled = undefined;
if (_trailing) {
this.send();
}
};
ThrottleSubscriber.prototype.notifyNext = function () {
this.throttlingDone();
};
ThrottleSubscriber.prototype.notifyComplete = function () {
this.throttlingDone();
};
return ThrottleSubscriber;
}(innerSubscribe_1.SimpleOuterSubscriber));
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