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51 lines
1.9 KiB
TypeScript
51 lines
1.9 KiB
TypeScript
1 month ago
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import { MonoTypeOperatorFunction, ObservableInput } from '../types';
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import { operate } from '../util/lift';
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import { createOperatorSubscriber } from './OperatorSubscriber';
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import { innerFrom } from '../observable/innerFrom';
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import { noop } from '../util/noop';
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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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*
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* Tick every second until the first click happens
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*
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* ```ts
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* import { interval, fromEvent, takeUntil } from 'rxjs';
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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 notifier The `ObservableInput` whose first emitted value will cause the output
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* Observable of `takeUntil` to stop emitting values from the source Observable.
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* @return A function that returns an Observable that emits the values from the
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* source Observable until `notifier` emits its first value.
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*/
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export function takeUntil<T>(notifier: ObservableInput<any>): MonoTypeOperatorFunction<T> {
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return operate((source, subscriber) => {
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innerFrom(notifier).subscribe(createOperatorSubscriber(subscriber, () => subscriber.complete(), noop));
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!subscriber.closed && source.subscribe(subscriber);
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});
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}
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