| import { Operator } from '../Operator'; |
| import { Subscriber } from '../Subscriber'; |
| import { Observable } from '../Observable'; |
| import { Subscription } from '../Subscription'; |
| import { MonoTypeOperatorFunction, SubscribableOrPromise, TeardownLogic } from '../types'; |
| |
| 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> |
| * |
| * ![](audit.png) |
| * |
| * `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 |
| * |
| * Emit clicks at a rate of at most one click per second |
| * ```ts |
| * import { fromEvent, interval } from 'rxjs'; |
| * import { audit } from 'rxjs/operators' |
| * |
| * const clicks = fromEvent(document, 'click'); |
| * const result = clicks.pipe(audit(ev => 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<T>(durationSelector: (value: T) => SubscribableOrPromise<any>): MonoTypeOperatorFunction<T> { |
| return function auditOperatorFunction(source: Observable<T>) { |
| return source.lift(new AuditOperator(durationSelector)); |
| }; |
| } |
| |
| class AuditOperator<T> implements Operator<T, T> { |
| constructor(private durationSelector: (value: T) => SubscribableOrPromise<any>) { |
| } |
| |
| call(subscriber: Subscriber<T>, source: any): TeardownLogic { |
| return source.subscribe(new AuditSubscriber<T, T>(subscriber, this.durationSelector)); |
| } |
| } |
| |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class AuditSubscriber<T, R> extends OuterSubscriber<T, R> { |
| |
| private value: T; |
| private hasValue: boolean = false; |
| private throttled: Subscription; |
| |
| constructor(destination: Subscriber<T>, |
| private durationSelector: (value: T) => SubscribableOrPromise<any>) { |
| super(destination); |
| } |
| |
| protected _next(value: T): void { |
| this.value = value; |
| this.hasValue = true; |
| if (!this.throttled) { |
| let duration; |
| try { |
| const { durationSelector } = this; |
| duration = durationSelector(value); |
| } catch (err) { |
| return this.destination.error(err); |
| } |
| const innerSubscription = subscribeToResult(this, duration); |
| if (!innerSubscription || 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: T, innerValue: R, outerIndex: number, innerIndex: number): void { |
| this.clearThrottle(); |
| } |
| |
| notifyComplete(): void { |
| this.clearThrottle(); |
| } |
| } |