Testing with Jest and Webpack aliases

when I use create-react-app my webpack aliases is

and my jest config is

import module like this

when I use npm run start , I can run my project correctly. But, when I use npm run test, it throw an error I can not find the module which i import in the last picture . How can I solve this ?

[Timer]

I suspect it’s because you have a $ (match end) in your Jest moduleNameMapper config, as ^kr$ does not match kr/utils.

You probably need a second case like ^kr[/](.+) which maps to <rootDir>/src/$1.

(your mileage may vary, this is an educated guess)

[Timer]

I’m going to close this since it isn’t very actionable by us. Basically, webpack knows a lot more about modules than Jest and knows how to remap all usages of kr for you. Jest relies on custom built regex by you, which requires you to match your slash-includes separately.

You can see https://github.com/facebook/jest/pull/1723 for more details.

Please try the changes mentioned above. If that doesn’t work, you might find success using jest-webpack-alias, but we cannot provide you with support whilst using that. It seems to me like you’re relying on additional tooling unnecessarily – perhaps you ejected too early without looking at alternatives to solve your problems.