FP-example.js

export const scheduleEpic = action$ => action$.pipe(
  ofType(FETCH_SCHEDULE_REQUEST),
  debounceTime(300),
  switchMap(({ payload }) => (
    ajax.getJSON(`${API_URL}/AvailableSeatStatusList/${payload.OriginStationID}`).pipe(
      map(response => ({
        ...payload,
        availableSeatTable: availableFormater(response[0], payload.DestinationStationID),
      })),
      catchError(error => of({
        type: FETCH_SCHEDULE_FAILURE,
        error: error.xhr.response,
      })),
    ))),
  switchMap(({
    availableSeatTable, OriginStationID, DestinationStationID, TrainDate,
  }) => {
    if (!availableSeatTable.length) return [fetchSuccess(availableSeatTable)];
    return ajax.getJSON(`${API_URL}/DailyTimetable/OD/${OriginStationID}/to/${DestinationStationID}/${TrainDate}`).pipe(
      map((response) => {
        const timeTable = timeTableFormater(response);
        return fetchSuccess(leftJoin(availableSeatTable, timeTable));
      }),
      catchError(error => of({
        type: FETCH_SCHEDULE_FAILURE,
        error: error.xhr.response,
      })),
    );
  }),

);