new-inj-4.ts

export function timespan$() {
  const activatedRoute = inject(ActivatedRoute);

  return activatedRoute.queryParams.pipe(
    pluck('timespan'),
    filterNil(),
    distinctUntilChanged()
  );
}

new-inj-5.ts

@Component({
  selector: 'app-todo-page',
  templateUrl: './todo-page.component.html'
})
export class TodoPageComponent {
  data$ = timespan$().pipe(
    switchMap(..)   
  )
}