'React' was used before it was defined

Question

I am working with create-react-app + typescript + eslint application and during build have such error:

Line 1:8:  \'React\' was used before it was defined  @t         


        

Answer 1

The bug occurs due to mismatch of @typescript-eslint versions in react-scripts and your local package.json - GitHub issue

You can downgrade the packages until react-scripts updates their version.

    "@typescript-eslint/eslint-plugin": "4.0.1",
    "@typescript-eslint/parser": "4.0.1",

EDIT 14/09/2020

It seems the bug is not related to react-scripts version of @typescript-eslint since multiple people reported the same bug without using react-scripts.

Anyway, the workaround remains the same - downgrade to the working version of @typescript-eslint until the fix is available.

EDIT 24/10/2020

react-scripts@4.0.0 has been published with updated @typescript-eslint. Using the newest version should solve the issue.

EDIT 04/11/2020

If after upgrading the packages the error is still there, most probably your eslint config uses the wrong rule. Check out Igor's answer to fix it.