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