import { Observable } from '../Observable';
import { SchedulerLike } from '../types';
/**
* The same Observable instance returned by any call to {@link empty} without a
* `scheduler`. It is preferable to use this over `empty()`.
*
* Just emits 'complete', and nothing else.
*
* 
*
* ## Examples
*
* ### Log complete notification
*
* ```ts
* import { EMPTY } from 'rxjs';
*
* EMPTY.subscribe({
* next: () => console.log('Next'),
* complete: () => console.log('Complete!')
* });
*
* // Outputs
* // Complete!
* ```
*/
export declare const EMPTY: Observable;
/**
* Creates an Observable that emits no items to the Observer and immediately
* emits a complete notification.
*
* Just emits 'complete', and nothing else.
*
* 
*
* This static operator is useful for creating a simple Observable that only
* emits the complete notification. It can be used for composing with other
* Observables, such as in a {@link mergeMap}.
*
* ## Examples
*
* ### Emit the number 7, then complete
*
* ```ts
* import { empty } from 'rxjs';
* import { startWith } from 'rxjs/operators';
*
* const result = empty().pipe(startWith(7));
* result.subscribe(x => console.log(x));
*
* // Outputs
* // 7
* ```
*
* ### Map and flatten only odd numbers to the sequence 'a', 'b', 'c'
*
* ```ts
* import { empty, interval, of } from 'rxjs';
* import { mergeMap } from 'rxjs/operators';
*
* const interval$ = interval(1000);
* const result = interval$.pipe(
* mergeMap(x => x % 2 === 1 ? of('a', 'b', 'c') : empty()),
* );
* result.subscribe(x => console.log(x));
*
* // Results in the following to the console:
* // x is equal to the count on the interval, e.g. (0, 1, 2, 3, ...)
* // x will occur every 1000ms
* // if x % 2 is equal to 1, print a, b, c (each on its own)
* // if x % 2 is not equal to 1, nothing will be output
* ```
*
* @see {@link Observable}
* @see {@link never}
* @see {@link of}
* @see {@link throwError}
*
* @param scheduler A {@link SchedulerLike} to use for scheduling
* the emission of the complete notification.
* @return An "empty" Observable: emits only the complete
* notification.
* @deprecated Replaced with the {@link EMPTY} constant or {@link scheduled} (e.g. `scheduled([], scheduler)`). Will be removed in v8.
*/
export declare function empty(scheduler?: SchedulerLike): Observable;
//# sourceMappingURL=empty.d.ts.map