ngrx-todos-effects-subscribe.ts

@Injectable()
export class TodosEffects {
  @Effect()
  public setTodos$ = this.actions$.pipe(
    ofType(Actions.GET_TODOS),
    exhaustMap(() => someService.getTodos()),
    map((todos) => ({
      type: Actions.SET_TODOS,
      payload: todos
    }))
  );

  constructor(private actions$: Actions) {}
}

// Псевдокод

todosEffectsInstance.setTodos$.subscribe(({ type, payload }) => {
  store.dispatch({ type, payload });
});