Jest: Jest seems not working with babel v7

[dnepro]

Do you want to request a _feature_ or report a _bug_?
_bug_

What is the current behavior?
I get an TypeError: Cannot read property 'loose' of undefined (While processing preset: "/Users/x/Desktop/jest-test/node_modules/babel-preset-react-app/index.js") on using jest v22.4.2 with babel v7

I've searched for this error and found this Bug in Babel, which 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.

If the current behavior is a bug, please provide the steps to reproduce and
either a repl.it demo through https://repl.it/languages/jest or a minimal
repository on GitHub that we can yarn install and yarn test.
I created this GitHub Repo

What is the expected behavior?
No error and it works with babel v7

Please provide your exact Jest configuration and mention your Jest, node,
yarn/npm version and operating system.

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

(all other dependencies can be found in the aforementioned GitHub Repo)

[dnepro]

Ahh forget it, in the Docs its npm install --save-dev babel-jest 'babel-core@^7.0.0-0' @babel/core regenerator-runtime, so both babel-core and @babel-core need to be installed 🤐 must have missed that, sorry ✌️

[SimenB]

so both babel-core and @babel-core need to be installed

yes

[bzmw]

Why both babel-core and @babel/core, is there a tracking issue for the package that is referring to babel-core?

[SimenB]

See https://github.com/babel/babel-bridge

[marcinczenko]

Just upgraded babel from 7.0.0-beta.44 to 7.0.0-beta.46 and all my tests fail with Unexpected token import. Looks like .babelrc is ignored. Is it known issue?

I see babel changes the way .babelrc files are discovered and it introduces babel.config.js, but I could not find any documentation. See:

https://github.com/babel/babel/releases/tag/v7.0.0-beta.45

and

https://github.com/babel/babel/pull/7784

[SimenB]

That's #6053

[marcinczenko]

Thanks - will check it out.

[hannadrehman]

same issue. i have @babel/core and babel-core@^7.0.0-0 installed.
the strange thing is when i try to use .babelrc' it works. but when i usebabel.config.jsit dosent work in that case. here is mybabel.config.js`

  const babelConfig = (api) => {
  // api.cache.never();
  const config = {
    presets: [
      ['@babel/preset-env', { modules: false, useBuiltIns: 'usage' }],
      '@babel/preset-react',
    ],
    plugins: [
      'react-hot-loader/babel',
      '@babel/plugin-proposal-object-rest-spread',
      '@babel/plugin-proposal-class-properties',
      '@babel/plugin-syntax-dynamic-import',
      ['import', { libraryName: 'antd', libraryDirectory: 'es', style: false }],
      [
        'module-resolver',
        {
          root: [
            './src',
          ],
          alias: {
            App: './src/App',
            Common: './src/App/Common',
            Elements: './src/App/Elements',
            Router: './src/App/Router',
            Constants: './src/Constants',
            Services: './src/Services',
            Store: './src/Store',
            Styles: './src/Styles',
            Assets: './src/Assets',
          },
        },
      ],
    ],
  };
  if (api.env('test')) {
    config.presets.splice(0, 1, ['@babel/preset-env', { useBuiltIns: 'usage' }]); // if i remove this nothing changes
    config.plugins.push('@babel/plugin-transform-modules-commonjs');
  }
  return config;
};

module.exports = babelConfig; 

[silverbackdan]

@hannadrehman I just had this issue and it worked in my docker container, I think it's the version of yarn that will cause this. 1.6.0 results in your issue, 1.7.0 seems to work well.

[dancon]

@hannadrehman i have the same issue.

[steveinatorx]

had similar issue - i could not get jest 24 to work with any combination of babel 7 when using latest yarn. i had to switch back to npm install which seemed to properly set up the dependent package hoisting.

[SimenB]

Jest 24 does not need the bridge at all

[steveinatorx]

pardon me. the bridge package was likely one of the many package combinations i tried to get jest 24 to work with babel 7. what worked for me was installing both @babel/core": "^7.2.2" and "babel-core": "^7.0.0-0", and switching from yarn to npm. i've edited the above comment to not include bridge package.

[viT-1]

@hannadrehman
I have the similar issue - tests failed with

TypeError: require(...) is not a function

It's happens after configuring @babel/polyfill https://babeljs.io/docs/en/babel-polyfill.

...
"@babel/core": "^7.2.2",
"babel-jest": "^24.1.0",
"jest": "^24.1.0",
...

Solved by changing { useBuiltIns: 'usage' } to { useBuiltIns: 'entry' }