Jest: babel-plugin-module-resolver aliases + jest watch bug

Created on 7 Mar 2018 · 7Comments · Source: facebook/jest

Here is the demo repo: https://github.com/cloud-walker/jest-module-resolver-bug steps to reproduce the bug are listed in the readme file.

What is the current behavior?
jest --watch -o will ignore deps imported using babel-plugin-module-resolver

What is the expected behavior?
I'm not sure if its possible, maybe I have to use the moduleNameMapper trick to make it work instead, but maybe it could work, so I'm notifying it.

Source

cloud-walker

Most helpful comment

Jest will not make assumptions on aliases based on the babel plugins you use. You'll need to tell Jest how to resolve these absolute aliases using moduleNameMapper:

  "jest": {
    "moduleNameMapper": {
      "@/(.*)": "<rootDir>/source/$1"
    }
  }

You'll also need to remove empty jest.config.js because Jest prioritizes it over package.json

thymikee on 25 May 2018

👍2 🎉1

All 7 comments

Have the same issue

chillyistkult on 21 Mar 2018

Jest will not make assumptions on aliases based on the babel plugins you use. You'll need to tell Jest how to resolve these absolute aliases using moduleNameMapper:

  "jest": {
    "moduleNameMapper": {
      "@/(.*)": "<rootDir>/source/$1"
    }
  }

You'll also need to remove empty jest.config.js because Jest prioritizes it over package.json

thymikee on 25 May 2018

👍2 🎉1

This is a little unfortunate if you have a monorepo structure with aliases. If each package uses the ~ prefix to signify the root of the package for imports then Jest will get confused when trying to resolve those imports in sibling packages.

If instead jest could honor the .babelrc in each package / transpile the package before running then it would be able to resolve aliases in sibling packages.

Right now I have to manually build (run babel) before running my tests so my alias imports get converted to relative imports and jest can resolve them correctly.

Happy to give more info if you have any questions about this setup.

dan-kez on 21 Jun 2018

Interesting solution Daniel, but it defeat part of the performance of jest
I guess T_T

Il giorno gio 21 giu 2018 alle ore 23:16 Daniel Kezerashvili <
[email protected]> ha scritto:

This is a little unfortunate if you have a monorepo structure with
aliases. If each package uses the ~ prefix to signify the root of the
package for imports then Jest will get confused when trying to resolve
those imports in sibling packages.

If instead jest could honor the .babelrc in each package / transpile the
package before running then it would be able to resolve aliases in sibling
packages.

Right now I have to manually build (run babel) before running my tests so
my alias imports get converted to relative imports and jest can resolve
them correctly.

Happy to give more info if you have any questions about this setup.

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cloud-walker on 21 Jun 2018

Another thought is for jest to look for the the jest config file relative to the file being imported and resolve the modules depending on its settings.

This way we don't necessarily lose the performance benefit but can have import resolution per package.

dan-kez on 22 Jun 2018

Hi to all, does anyone find a solution to this? I think i'm encountering the same issue. I keep getting the same error: error TS2307: Cannot find module
i'm using next.js, typescript, jest and enzyme and i also have installed the babel plugin module resolver.

Emiliano-Bucci on 8 Nov 2018

why is this closed? I'm facing the same issue. It makes much more intuitive sense for alias configuration to be inherited from babel config when babel-jest is used