jest 24 with babel 6 and babel-jest 23

[blackpost38]

Hi, thanks for advance.

My project has babel 6.x . So i installed [email protected] and [email protected]. Because according to docs babel 6 is required jest 23.x or jest 24.x with babel-jest 23.x.

But when i run test code with jest, i got fail with error message like this

Plugin/Preset files are not allowed to export objects, only functions. In C:\workspaces\lbd2\lbd2_vue\node_modules\babel-preset-stage-2\lib\index.js

My question is when i use babel 6, is it right to install jest 24.x with babel-jest 23.x? Or is there something that i misunderstand?

[SimenB]

Please follow the templates (particularly include a reproduction). Happy to reopen once a reproduction is added

[anatoliyarkhipov]

The issue can be reproduced if Babel setup uses some presets (I suppose they're kinda "old-style" or something like that):

$ cat package.json
{
  "name": "jest-reproduction",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "jest"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "babel-core": "^6.26.3",
    "babel-jest": "^23.6.0",
    "babel-preset-env": "^1.7.0",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-react": "^6.24.1",
    "babel-preset-stage-1": "^6.24.1",
    "jest": "^24.5.0",
    "react-hot-loader": "^4.8.0"
  }
}

$ cat .babelrc
{
  "presets": ["es2015", "react", "stage-1"]
}

Any of the presets in the example above (and stage-2 as we can see from the original issue description) produce the error:

$ npm jest
Plugin/Preset files are not allowed to export objects, only functions. In  \jest-reproduction\node_modules\babel-preset-es2015\lib\index.js

[jochakovsky]

@SimenB I've created a reproduction repo, can you please re-open? Thanks!

https://github.com/jochakovsky/Jest-24-Babel-6-preset-bug - just need to clone, run yarn install and yarn run test.

One workaround I've found is to add "resolutions": {"babel-jest": "23.6.0"} to package.json, though this is hacky and yarn-specific.