Mocking scoped package libraries

I’ve been working on migrating a project which we ejected some time ago back into CRA.

I’ve come across a problem with the way we are mocking scoped packages. We were using the moduleNameMapper in the jest section of our package.json like this:

package.json

"jest": {
  "moduleNameMapper": {
    "^@org-name/package-one$": "<rootDir>/__mocks__/org-name/package-one/dist/package.js",
    "^@org-name/package-two$": "<rootDir>/__mocks__/org-name/package-two/build/index.js"
  }
}

When I add this to the un-ejected CRA project I get the following error:

These options in your package.json Jest configuration are not currently supported by Create React App:

  • moduleNameMapper

If you wish to override other Jest options, you need to eject from the default setup. You can do so by running npm run eject but remember that this is a one-way operation. You may also file an issue with Create React App to discuss supporting more options out of the box.

Any ideas how I can get these mocks working?

[nareshbhatia]

I have created PR https://github.com/facebook/create-react-app/pull/6633 to support merging of external moduleNameMapper configuration with react-scripts’ internal configuration. I believe its a win-win solution. Hopefully everyone agrees.

[skarode96]

I was trying to run the Jest test suite in my local environment! I created a jest.config.js in the root directory of my project and moved the configs of Jest from package.json to jest.config.js module.exports = { moduleNameMapper: { "\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "jest-transform-stub", "\\.(css|less|scss|sass)$": "identity-obj-proxy" } }; and while running the test suite on local machine, I have provided the config path to IDE as jest.config.js and test suite is running successfully.

also while running tests through cmd npm run test it is running without errors !