React JSX file giving error “Cannot read property 'createElement' of undefined”

Question

I have a file test_stuff.js that I am running with npm test

It pretty much looks like this:

import { assert } from 'assert';
import { MyProvider } from '../src/index';
import { React } from 'react';

const myProvider = (
  <MyProvider>
  </MyProvider>
);

describe('Array', function() {
  describe('#indexOf()', function() {
    it('should return -1 when the value is not present', function() {
      assert.equal(-1, [1,2,3].indexOf(4));
    });
  });
});

Unfortunately, I get the error

/Users/me/projects/myproj/test/test_stuff.js:11
var myProvider = _react.React.createElement(_index.MyProvider, null);
                             ^

TypeError: Cannot read property 'createElement' of undefined
    at Object.<anonymous> (/Users/me/projects/myproj/test/test_stuff.js:7:7)

What does that mean? I am importing React from 'react' successfully, so why would React be undefined? It is _react.React, whatever that means...

Answer 1

To import React do import React from 'react' You add brackets when the thing you are importing is not the default export in that module or file. In case of react, it's the default export.

This might apply to your other imports depending on how you defined them.

Answer 2

import React, { Component } from 'react'

This worked for me. I'm not sure why it fixed my version of this issue, though. So if you are someone who stumbled upon this problem and you use create-react-app as your starting boilerplate, this way of importing React will do the trick. (as of Oct '18, lol)

Answer 3

For those who are working ReactJS with TypeScript.

import * as React from 'react';

Answer 4

This error occured to me due to carelessness. It's actually

import React from 'react';

Brackets are for named exports such as this:

import React, { useState, useEffect } from 'react';

Answer 5

Change: import { React } from 'react' to import React from 'react' Because React is a default export and you don’t need curly braces for any default exports.

Answer 6

If in case you need to import multiple classes from 'react', you can have an alias for them except React. Something like,

import React, * as react from 'react';

Answer 7

React is exported by default in that module, no need {}.

Answer 8

Trying to use destructor for importing the React object may cause you problems like this import {React} from 'react';. This might be the cause of the error 90% of the time running this code above.

rather use: import React from 'react';

And then you can access any member of the React class via: React.