import { Operator } from '../Operator';
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import { Observable } from '../Observable';
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import { Subscriber } from '../Subscriber';
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import { MonoTypeOperatorFunction, TeardownLogic } from '../types';
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import { innerSubscribe, SimpleInnerSubscriber, SimpleOuterSubscriber } from '../innerSubscribe';
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/**
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* Emits the values emitted by the source Observable until a `notifier`
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* Observable emits a value.
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*
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* <span class="informal">Lets values pass until a second Observable,
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* `notifier`, emits a value. Then, it completes.</span>
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*
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* 
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*
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* `takeUntil` subscribes and begins mirroring the source Observable. It also
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* monitors a second Observable, `notifier` that you provide. If the `notifier`
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* emits a value, the output Observable stops mirroring the source Observable
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* and completes. If the `notifier` doesn't emit any value and completes
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* then `takeUntil` will pass all values.
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*
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* ## Example
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* Tick every second until the first click happens
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* ```ts
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* import { fromEvent, interval } from 'rxjs';
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* import { takeUntil } from 'rxjs/operators';
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*
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* const source = interval(1000);
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* const clicks = fromEvent(document, 'click');
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* const result = source.pipe(takeUntil(clicks));
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* result.subscribe(x => console.log(x));
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* ```
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*
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* @see {@link take}
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* @see {@link takeLast}
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* @see {@link takeWhile}
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* @see {@link skip}
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*
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* @param {Observable} notifier The Observable whose first emitted value will
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* cause the output Observable of `takeUntil` to stop emitting values from the
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* source Observable.
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* @return {Observable<T>} An Observable that emits the values from the source
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* Observable until such time as `notifier` emits its first value.
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* @method takeUntil
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* @owner Observable
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*/
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export function takeUntil<T>(notifier: Observable<any>): MonoTypeOperatorFunction<T> {
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return (source: Observable<T>) => source.lift(new TakeUntilOperator(notifier));
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}
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class TakeUntilOperator<T> implements Operator<T, T> {
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constructor(private notifier: Observable<any>) {
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}
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call(subscriber: Subscriber<T>, source: any): TeardownLogic {
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const takeUntilSubscriber = new TakeUntilSubscriber(subscriber);
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const notifierSubscription = innerSubscribe(this.notifier, new SimpleInnerSubscriber(takeUntilSubscriber));
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if (notifierSubscription && !takeUntilSubscriber.seenValue) {
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takeUntilSubscriber.add(notifierSubscription);
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return source.subscribe(takeUntilSubscriber);
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}
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return takeUntilSubscriber;
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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 TakeUntilSubscriber<T, R> extends SimpleOuterSubscriber<T, R> {
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seenValue = false;
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constructor(destination: Subscriber<any>, ) {
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super(destination);
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}
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notifyNext(): void {
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this.seenValue = true;
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this.complete();
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}
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notifyComplete(): void {
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// noop
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}
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}
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