biobulkbende.org/node_modules/rxjs/_esm2015/operators/audit.js
2020-09-16 14:23:28 +02:00

108 lines
3.9 KiB
JavaScript

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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