es6/operators/audit.js

import { tryCatch } from '../util/tryCatch';
import { errorObject } from '../util/errorObject';
import { OuterSubscriber } from '../OuterSubscriber';
import { subscribeToResult } from '../util/subscribeToResult';
/**
 * Ignores source values for a duration determined by another Observable, then
 * emits the most recent value from the source Observable, then repeats this
 * process.
 *
 * <span class="informal">It's like {@link auditTime}, but the silencing
 * duration is determined by a second Observable.</span>
 *
 * <img src="./img/audit.png" width="100%">
 *
 * `audit` is similar to `throttle`, but emits the last value from the silenced
 * time window, instead of the first value. `audit` emits the most recent value
 * from the source Observable on the output Observable as soon as its internal
 * timer becomes disabled, and ignores source values while the timer is enabled.
 * Initially, the timer is disabled. As soon as the first source value arrives,
 * 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, then the most
 * recent source value is emitted on the output Observable, 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.audit(ev => Rx.Observable.interval(1000));
 * result.subscribe(x => console.log(x));
 *
 * @see {@link auditTime}
 * @see {@link debounce}
 * @see {@link delayWhen}
 * @see {@link sample}
 * @see {@link throttle}
 *
 * @param {function(value: T): SubscribableOrPromise} durationSelector A function
 * that receives a value from the source Observable, for computing the silencing
 * duration, returned as an Observable or a Promise.
 * @return {Observable<T>} An Observable that performs rate-limiting of
 * emissions from the source Observable.
 * @method audit
 * @owner Observable
 */
export function audit(durationSelector) {
    return function auditOperatorFunction(source) {
        return source.lift(new AuditOperator(durationSelector));
    };
}
class AuditOperator {
    constructor(durationSelector) {
        this.durationSelector = durationSelector;
    }
    call(subscriber, source) {
        return source.subscribe(new AuditSubscriber(subscriber, this.durationSelector));
    }
}
/**
 * We need this JSDoc comment for affecting ESDoc.
 * @ignore
 * @extends {Ignored}
 */
class AuditSubscriber extends OuterSubscriber {
    constructor(destination, durationSelector) {
        super(destination);
        this.durationSelector = durationSelector;
        this.hasValue = false;
    }
    _next(value) {
        this.value = value;
        this.hasValue = true;
        if (!this.throttled) {
            const duration = tryCatch(this.durationSelector)(value);
            if (duration === errorObject) {
                this.destination.error(errorObject.e);
            }
            else {
                const innerSubscription = subscribeToResult(this, duration);
                if (innerSubscription.closed) {
                    this.clearThrottle();
                }
                else {
                    this.add(this.throttled = innerSubscription);
                }
            }
        }
    }
    clearThrottle() {
        const { value, hasValue, throttled } = this;
        if (throttled) {
            this.remove(throttled);
            this.throttled = null;
            throttled.unsubscribe();
        }
        if (hasValue) {
            this.value = null;
            this.hasValue = false;
            this.destination.next(value);
        }
    }
    notifyNext(outerValue, innerValue, outerIndex, innerIndex) {
        this.clearThrottle();
    }
    notifyComplete() {
        this.clearThrottle();
    }
}
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