text: import {
      AUTH_USER,
      UNAUTH_USER,
      AUTH_ERROR,
      FETCH_MESSAGE
  } from '../actions/types';
  
  export default function( state= {}, action) {
      switch(action.type){
          case AUTH_USER:
              return {...state, error: '', authenticated: true};
          case UNAUTH_USER:
              return {...state, authenticated: false};
          case AUTH_ERROR:
              return {...state, error: action.payload};
          case FETCH_MESSAGE:
              return {...state, message: action.payload};
  
      }
  
      return state;
  }