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[6a3a178] | 1 | import { Observable } from '../Observable';
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| 2 | import { noop } from '../util/noop';
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| 3 |
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| 4 | /**
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| 5 | * An Observable that emits no items to the Observer and never completes.
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| 6 | *
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| 7 | * ![](never.png)
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| 8 | *
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| 9 | * A simple Observable that emits neither values nor errors nor the completion
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| 10 | * notification. It can be used for testing purposes or for composing with other
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| 11 | * Observables. Please note that by never emitting a complete notification, this
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| 12 | * Observable keeps the subscription from being disposed automatically.
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| 13 | * Subscriptions need to be manually disposed.
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| 14 | *
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| 15 | * ## Example
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| 16 | * ### Emit the number 7, then never emit anything else (not even complete)
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| 17 | * ```ts
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| 18 | * import { NEVER } from 'rxjs';
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| 19 | * import { startWith } from 'rxjs/operators';
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| 20 | *
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| 21 | * function info() {
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| 22 | * console.log('Will not be called');
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| 23 | * }
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| 24 | * const result = NEVER.pipe(startWith(7));
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| 25 | * result.subscribe(x => console.log(x), info, info);
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| 26 | *
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| 27 | * ```
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| 28 | *
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| 29 | * @see {@link Observable}
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| 30 | * @see {@link index/EMPTY}
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| 31 | * @see {@link of}
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| 32 | * @see {@link throwError}
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| 33 | */
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| 34 | export const NEVER = new Observable<never>(noop);
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| 35 |
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| 36 | /**
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| 37 | * @deprecated Deprecated in favor of using {@link NEVER} constant.
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| 38 | */
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| 39 | export function never () {
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| 40 | return NEVER;
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| 41 | }
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