finalize / finally

signature: finalize(callback: () => void)

Call a function when observable completes or errors

Examples

Example 1: Execute callback function when the observable completes

( StackBlitz )

import { interval } from 'rxjs';
import { take, finalize } from 'rxjs/operators';

//emit value in sequence every 1 second
const source = interval(1000);
//output: 0,1,2,3,4,5....
const example = source.pipe(
  take(5), //take only the first 5 values
  finalize(() => console.log('Sequence complete')) // Execute when the observable completes
)
const subscribe = example.subscribe(val => console.log(val));

Related Recipes

• HTTP Polling

Additional Resources

• finalize - Official docs

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