Uncaught ReferenceError: React is not defined

Question

I am trying to make ReactJS work with rails using this tutorial. I am getting this error:

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Uncaught ReferenceError: React is not defined

Answer 1

Try to add:

import React from 'react'
import { render } from 'react-dom'
window.React = React

before the render() function.

This sometimes prevents error to pop-up returning:

React is not defined

Adding React to the window will solve these problems.