ignoreElements

signature: ignoreElements(): Observable

Ignore everything but complete and error.

Ultimate RxJS

Examples

Example 1: Ignore all elements from source

( StackBlitz | jsBin | jsFiddle )

// RxJS v6+
import { interval } from 'rxjs';
import { take, ignoreElements } from 'rxjs/operators';
//emit value every 100ms
const source = interval(100);
//ignore everything but complete
const example = source.pipe(
take(5),
ignoreElements()
);
//output: "COMPLETE!"
const subscribe = example.subscribe(
val => console.log(`NEXT: ${val}`),
val => console.log(`ERROR: ${val}`),
() => console.log('COMPLETE!')
);

Example 2: Only displaying error

( StackBlitz | jsBin | jsFiddle )

// RxJS v6+
import { interval, throwError, of } from 'rxjs';
import { mergeMap, ignoreElements } from 'rxjs/operators';
//emit value every 100ms
const source = interval(100);
//ignore everything but error
const error = source.pipe(
mergeMap(val => {
if (val === 4) {
return throwError(`ERROR AT ${val}`);
}
return of(val);
}),
ignoreElements()
);
//output: "ERROR: ERROR AT 4"
const subscribe = error.subscribe(
val => console.log(`NEXT: ${val}`),
val => console.log(`ERROR: ${val}`),
() => console.log('SECOND COMPLETE!')
);

Additional Resources

📁 Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/ignoreElements.ts