validation code saga with user grouping and throttling

validation-code.saga.ts

const VALIDATION_CODE_THROTTLE_TIME_IN_MS = 5000;
const getUserId = ({ payload: { user } }: ValidationCodeGeneratedEvent): User["id"] => user.id;

@Injectable()
export class ValidationCodeSagas {
  @Saga()
  ValidationCodeRequested = (event$: Observable<IEvent>): Observable<SendValidationCodeCommand> => {
    return event$.pipe(
      ofType(ValidationCodeGeneratedEvent),
      groupBy(getUserId),
      mergeMap((group$) => group$.pipe(throttleTime(VALIDATION_CODE_THROTTLE_TIME_IN_MS))),
      map(({ payload }) => new SendValidationCodeCommand(payload)),
    );
  };
}