node_modules/rxjs/_esm5/operators/throttleTime.js

/** PURE_IMPORTS_START .._Subscriber,.._scheduler_async,._throttle PURE_IMPORTS_END */
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 __());
};
import { Subscriber } from '../Subscriber';
import { async } from '../scheduler/async';
import { defaultThrottleConfig } from './throttle';
/**
 * Emits a value from the source Observable, then ignores subsequent source
 * values for `duration` milliseconds, then repeats this process.
 *
 * <span class="informal">Lets a value pass, then ignores source values for the
 * next `duration` milliseconds.</span>
 *
 * <img src="./img/throttleTime.png" width="100%">
 *
 * `throttleTime` 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. After `duration` milliseconds (or the time unit determined
 * internally by the optional `scheduler`) has passed, the timer is disabled,
 * and this process repeats for the next source value. Optionally takes a
 * {@link IScheduler} for managing timers.
 *
 * @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.throttleTime(1000);
 * result.subscribe(x => console.log(x));
 *
 * @see {@link auditTime}
 * @see {@link debounceTime}
 * @see {@link delay}
 * @see {@link sampleTime}
 * @see {@link throttle}
 *
 * @param {number} duration Time to wait before emitting another value after
 * emitting the last value, measured in milliseconds or the time unit determined
 * internally by the optional `scheduler`.
 * @param {Scheduler} [scheduler=async] The {@link IScheduler} to use for
 * managing the timers that handle the throttling.
 * @return {Observable<T>} An Observable that performs the throttle operation to
 * limit the rate of emissions from the source.
 * @method throttleTime
 * @owner Observable
 */
export function throttleTime(duration, scheduler, config) {
    if (scheduler === void 0) {
        scheduler = async;
    }
    if (config === void 0) {
        config = defaultThrottleConfig;
    }
    return function (source) { return source.lift(new ThrottleTimeOperator(duration, scheduler, config.leading, config.trailing)); };
}
var ThrottleTimeOperator = /*@__PURE__*/ (/*@__PURE__*/ function () {
    function ThrottleTimeOperator(duration, scheduler, leading, trailing) {
        this.duration = duration;
        this.scheduler = scheduler;
        this.leading = leading;
        this.trailing = trailing;
    }
    ThrottleTimeOperator.prototype.call = function (subscriber, source) {
        return source.subscribe(new ThrottleTimeSubscriber(subscriber, this.duration, this.scheduler, this.leading, this.trailing));
    };
    return ThrottleTimeOperator;
}());
/**
 * We need this JSDoc comment for affecting ESDoc.
 * @ignore
 * @extends {Ignored}
 */
var ThrottleTimeSubscriber = /*@__PURE__*/ (/*@__PURE__*/ function (_super) {
    __extends(ThrottleTimeSubscriber, _super);
    function ThrottleTimeSubscriber(destination, duration, scheduler, leading, trailing) {
        _super.call(this, destination);
        this.duration = duration;
        this.scheduler = scheduler;
        this.leading = leading;
        this.trailing = trailing;
        this._hasTrailingValue = false;
        this._trailingValue = null;
    }
    ThrottleTimeSubscriber.prototype._next = function (value) {
        if (this.throttled) {
            if (this.trailing) {
                this._trailingValue = value;
                this._hasTrailingValue = true;
            }
        }
        else {
            this.add(this.throttled = this.scheduler.schedule(dispatchNext, this.duration, { subscriber: this }));
            if (this.leading) {
                this.destination.next(value);
            }
        }
    };
    ThrottleTimeSubscriber.prototype.clearThrottle = function () {
        var throttled = this.throttled;
        if (throttled) {
            if (this.trailing && this._hasTrailingValue) {
                this.destination.next(this._trailingValue);
                this._trailingValue = null;
                this._hasTrailingValue = false;
            }
            throttled.unsubscribe();
            this.remove(throttled);
            this.throttled = null;
        }
    };
    return ThrottleTimeSubscriber;
}(Subscriber));
function dispatchNext(arg) {
    var subscriber = arg.subscriber;
    subscriber.clearThrottle();
}
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