text: import {
      AUTH_USER,
      UNAUTH_USER, 
      AUTH_ERROR,
      FETCH_MESSAGE
  } from '../actions/types';
  
  export default (state = {}, action) => {
      switch (action.type) {
          case AUTH_USER:
              return { ...state, 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 };
          default:
              return state; 
      }
  };
  