import { OperatorFunction } from '../types';
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import { operate } from '../util/lift';
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import { createOperatorSubscriber } from './OperatorSubscriber';
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import { noop } from '../util/noop';
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/**
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* Ignores all items emitted by the source Observable and only passes calls of `complete` or `error`.
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*
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* 
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*
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* The `ignoreElements` operator suppresses all items emitted by the source Observable,
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* but allows its termination notification (either `error` or `complete`) to pass through unchanged.
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*
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* If you do not care about the items being emitted by an Observable, but you do want to be notified
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* when it completes or when it terminates with an error, you can apply the `ignoreElements` operator
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* to the Observable, which will ensure that it will never call its observers’ `next` handlers.
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*
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* ## Example
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*
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* Ignore all `next` emissions from the source
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*
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* ```ts
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* import { of, ignoreElements } from 'rxjs';
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*
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* of('you', 'talking', 'to', 'me')
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* .pipe(ignoreElements())
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* .subscribe({
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* next: word => console.log(word),
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* error: err => console.log('error:', err),
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* complete: () => console.log('the end'),
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* });
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*
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* // result:
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* // 'the end'
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* ```
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*
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* @return A function that returns an empty Observable that only calls
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* `complete` or `error`, based on which one is called by the source
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* Observable.
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*/
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export function ignoreElements(): OperatorFunction<unknown, never> {
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return operate((source, subscriber) => {
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source.subscribe(createOperatorSubscriber(subscriber, noop));
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});
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}
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