Redux reducers refactored using ES2015 enhanced object literals

reducers.js

import { combineReducers } from 'redux';
import { LOGIN, LOGOUT } from './action-types';
const initialState = {};

const user = (state = initialState, action) => {
  const actionTypeHandlerMap = {
    [LOGIN]: ({ status, userInfo }) => ({ ...state, status, userInfo }),
    [LOGOUT]: ({ status }) => ({ ...state, status, userInfo: {}}),
    [undefined]: () => state
  }

  return actionTypeHandlerMap[action.type](action);
}

export default combineReducers({ user });