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