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  • #13009
Closed
Open
Issue created Feb 09, 2023 by Administrator@rootContributor

react-scripts start bug: Class extends value undefined is not a constructor or null

Created by: MajorMeerkatThe3rd

Describe the bug

It seems like the build process changed and now throws an error where there previously wasn't one. In react-scripts version 4.0.3 everything works just fine, whereas in version 5.0.1 I get the error Class extends value undefined is not a constructor or null.

Did you try recovering your dependencies?

Yes, I tried multiple setups and multiple repos. The error does not seem to be npm-version dependent. npm: 8.1.2

Which terms did you search for in User Guide?

webpack, require, setup

Environment

Environment Info:

current version of create-react-app: 5.0.1 running from C:\Users\main\AppData\Local\npm-cache_npx\c67e74de0542c87c\node_modules\create-react-app

System: OS: Windows 10 10.0.19044 CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz Binaries: Node: 16.13.1 - C:\Program Files\nodejs\node.EXE Yarn: Not Found npm: 8.1.2 - C:\Program Files\nodejs\npm.CMD Browsers: Chrome: Not Found Edge: Spartan (44.19041.1266.0), Chromium (101.0.1210.53) Internet Explorer: 11.0.19041.1566 npmPackages: react: 18.0.0 => 18.0.0 react-dom: 18.0.0 => 18.0.0 react-scripts: 5.0.1 => 4.0.3 npmGlobalPackages: create-react-app: Not Found

Steps to reproduce

my example repo

  1. Go to the repository that I just created for this.
  2. Try npm start with the version 4.0.3 and version 5.0.1. For 5.0.1 you will get the mentioned error in the console.
  3. For 4.0.3 everything works as expected.
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