Element type is invalid: expected a string (for built-in components) or a class/function

Question

import React from \'react\';
import ReactDOM from \'react-dom\';
import Map from \'./components/map/container/map\';
import App from \'./App\';
import \'./index.css\         


        

Answer 1

As was sayed above, this issue with import. In my case it's was a CSSTransitionGroup import. After npm update the package 'react-transition-group' no longer contains CSSTransitionGroup, but it's contains different exports, like CSSTransition and TransitionGroup. So i just replace line:

import CSSTransitionGroup from 'react-transition-group/CSSTransitionGroup'; 

with

import TransitionGroup from 'react-transition-group/TransitionGroup';