Sometimes, we want to fix the ‘Uncaught ReferenceError: React is not defined’ error when developing React apps.

In this article, we’ll look at how to fix the ‘Uncaught ReferenceError: React is not defined’ error when developing React apps.

Fix the ‘Uncaught ReferenceError: React is not defined’ Error When Developing React Apps

To fix the ‘Uncaught ReferenceError: React is not defined’ error when developing React apps, we can add the 'react' property to the externals property in webpack.config.json.

To do this, we write:

externals: {
    'react': 'React'
},

to tell Webpack that React a global variable.

Also, we can add import React from 'react'; to the top of each component file to fix the error.

Conclusion

To fix the ‘Uncaught ReferenceError: React is not defined’ error when developing React apps, we can add the 'react' property to the externals property in webpack.config.json.

Also, we can add import React from 'react'; to the top of each component file to fix the error.