Push new objects to array upon DATA_SUCCESS action from api get request

gistfile1.txt

const initialState = {
  fieldMap = []
}

// take result, push objects to fielMap array
const createFieldMap = (result, fieldMap, fieldMapMade) => {
  if (!fieldMapMade) {
    result.headers.map((key, index) => {
      const cardIndex = index;
      const samplesArr = [];
      result.samples.map((sample) => {
        const newArray = __.at(sample, cardIndex).toString() || '-';
        samplesArr.push(newArray);
      });
      fieldMap.push({header: key, dataType: '', samples: samplesArr});
    });
    return { fieldMap };
  }
};


// when I get the result from the API (scala api), i run this function to push results to fieldMap array -
case DATA_SUCCESS:
  return {
    ...state,
    next: createFieldMap(action.result, state.fieldMap, state.fieldMapMade),
    response: action.res,
    gotData: true,
    error: null,
  };
  
// Action Creator
export function loadClientData(clientId, userEmail, fileName) {
  return {
    types: [ LOAD_DATA, DATA_SUCCESS, DATA_FAILURE ],
    promise: (client) => client.get('/v3/client/' + clientId + '/files/' + fileName + '/sample', {
      headers: { 'userEmail': userEmail, 'name': fileName }
    })
  };
}