Jest-Test

Demo Repository for Jest Issue #5736

How to

1. run npm i
2. run npm test
3. see error TypeError: Cannot read property 'loose' of undefined (While processing preset: "/Users/x/Desktop/jest-test/node_modules/babel-preset-react-app/index.js")

Further

I've searched for this error and found this Babel issue, that suggests that when babel-core instead of @babel/core is required by any package, it will break. And it seems like jest-runtime v22.4.2 (currently the newest one) is doing exactly this.

System

• Operating System: MacOS 10.13.2 (High Sierra)
• Nodejs: v9.4.0
• npm: v5.7.1