Creates an Observable that emits no items to the Observer and immediately
emits a complete notification.
Deprecation Notes
Deprecated in favor of using EMPTY constant.
empty(scheduler?: SchedulerLike)
Parameters
| scheduler |
Optional. Default is undefined.
A SchedulerLike to use for scheduling
the emission of the complete notification.
|
Description
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 mergeMap.
Examples
Emit the number 7, then complete
import { empty } from 'rxjs';
import { startWith } from 'rxjs/operators';
const result = empty().pipe(startWith(7));
result.subscribe(x => console.log(x));
Map and flatten only odd numbers to the sequence 'a', 'b', 'c'
import { empty, interval } from 'rxjs';
import { mergeMap } from 'rxjs/operators';
const interval$ = interval(1000);
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 eg(0,1,2,3,...)
// x will occur every 1000ms
// if x % 2 is equal to 1 print abc
// if x % 2 is not equal to 1 nothing will be output