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babel@7 and jest configuration


Maybe you may help me? I try to configure jest to use babel@7 So I have:

"jest": "^23.4.1",
"@babel/core": "^7.0.0-beta.54",
"babel-7-jest": "^21.3.3",
"babel-jest": "^20.0.3",

And jest config inside package.json

"jest": {
    "transform": {
      "^.+\\.js$": "babel-7-jest",
    },

And got

TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string

But if I use

"jest": {
    "transform": {
      "^.+\\.js$": "babel-jest",
    },

I got

Requires Babel "^7.0.0-0", but was loaded with "6.26.3". If you are sure you have a compatible version of @babel/core, it is likely that something in your build process is loading the wrong version. Inspect the stack trace of this error to look for the first entry that doesn't mention "@babel/core" or "babel-core" to see what is calling Babel.

babel config: https://gist.github.com/SilentImp/1506e9c26d16d9839a4469c6f3ae5c4d

Maybe you have some ideas?


Solution

  • I believe I have found a working solution (no thanks to the Jest team providing broken documentation and evading GitHub issues around this issue).

    You need the following in your devDependencies section of your package.json:

      "devDependencies": {
        "@babel/core": "^7.0.0-beta.54",
        "@babel/preset-env": "^7.0.0-beta.54",
        "babel-core": "^7.0.0-bridge.0",
        "babel-jest": "^23.4.0",
        "bili": "^3.1.2",
        "jest": "^23.4.1",
        "regenerator-runtime": "^0.12.0"
      }
    

    The following in your .babelrc:

    {
        "presets": [
            [
                "@babel/preset-env",
                {
                    "debug": false,
                    "targets": {
                        "browsers": [
                            "last 3 versions"
                        ]
                    }
                }
            ]
        ]
    }
    

    In my particular project I did not need to use the Jest config so I deleted my empty jest.config.js file.

    Key points:

    • Remove babel-7-jest as this is deprecated as there is now official support for it.
    • Make sure to only use @babel/xyz packages going forward - the babel-core bridge one I have installed is the "official" way to use latest Babel 7. I imagine this need will be removed at some point in the future as everything migrates to Babel 7.
    • You can now use ES6+ features including import/export and no longer need the antiquated require().

    Edit:

    If you want to have a more detailed log of passing/failing tests then put this in your jest.config.js:

    module.exports = {
        "verbose": true   
    }