import { of } from 'rxjs'; import { finalize } from 'rxjs/operators'; it('should infer correctly', () => { const o = of(1, 2, 3).pipe(finalize(() => {})); // $ExpectType Observable }); it('should enforce types', () => { const o = of(1, 2, 3).pipe(finalize()); // $ExpectError const p = of(1, 2, 3).pipe(finalize((value => {}))); // $ExpectError });