Testing with Jest and Webpack aliases

Question

I am looking to be able to use webpack aliases to resolve imports when using jest, and optimally, reference the webpack.aliases to avoid duplication.

Jest conf:

  "jest": {
    "modulePaths": ["src"],
    "moduleDirectories": ["node_modules"],
    "moduleNameMapper": {
      "^@shared$": "<rootDir>/shared/",
      "^@components$": "<rootDir>/shared/components/"
    }
  },

Webpack aliases:

exports.aliases = {
    '@shared': path.resolve(paths.APP_DIR, 'shared'),
    '@components': path.resolve(paths.APP_DIR, 'shared/components'),
};

Imports:

import Ordinal from '@shared/utils/Ordinal.jsx';
import Avatar from '@components/common/Avatar.jsx';

For some reason the @ causes issues, so when removed (in both alias and import), it can find shared but components still cannot be resolved.

 FAIL  src/shared/components/test/Test.spec.jsx
  ● Test suite failed to run

    Cannot find module '@shared/utils/Ordinal.jsx' from 'Test.jsx'

I have tried using jest-webpack-alias, babel-plugin-module-resolver and the Jest/Webpack docs

Answer 1

Since I had the same problem before I read again, and this time more carefully the documentation. Correct config should be:

  "jest": {
    "moduleNameMapper": {
      "^@shared(.*)$": "<rootDir>/shared$1",
      "^@components(.*)$": "<rootDir>/shared/components$1"
    }
  },