babel@7 and jest configuration

Question

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\         


        

Answer 1

I have struggled with this issue for a few days with no luck until seeing this post. Thanks so much for everyone posting whats worked from them!

Here is my configuration for clarity. This is a VueJs application using Jest. Hope this helps someone :)

My npm script for tests

"test:unit": "jest --config ./jest.config.js"

My babel packages

    "@babel/core": "^7.6.2",
    "babel-loader": "^8.0.4",
    "babel-core": "^7.0.0-bridge.0",
    "@babel/preset-env": "^7.6.2",
    "babel-eslint": "^10.0.1",
    "babel-jest": "^23.6.0",
    "@vue/cli-plugin-babel": "^3.11.0",

babel.config.js

module.exports = {
    presets: [
        [
            '@babel/preset-env',
            {
                debug: false,
                targets: {
                    browsers: ['last 3 versions'],
                },
            },
        ],
    ],
};

jest.confg.js

module.exports = {
    verbose: true,
    moduleFileExtensions: ['js', 'json', 'vue'],
    moduleNameMapper: {
        '^@/(.*)$': '<rootDir>/src/$1',
    },
    transform: {
        '^.+\\.vue$': 'vue-jest',
        '.+\\.(css|styl|less|sass|scss|png|jpg|ttf|woff|woff2)$': 'jest-transform-stub',
        '^.+\\.(js|jsx)?$': 'babel-jest',
    },
    transformIgnorePatterns: ['<rootDir>/node_modules/'],
    testMatch: ['**/tests/unit/**/*.spec.(js|jsx|ts|tsx)|**/__tests__/*.(js|jsx|ts|tsx)'],
    collectCoverage: false,
    collectCoverageFrom: ['src/components/*.{js,vue}', '!**/node_modules/**'],
    coverageReporters: ['html', 'text-summary'],
};

Answer 2

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   
}

Answer 3

4 days ago Facebook added babel 7 support for jest, so no need use the babel 7 bridge anymore.

For more information: https://github.com/facebook/jest/blob/master/README.md#using-babel

Answer 4

You can find a working example and tutorial over here.

These are all my Babel packages:

"@babel/core": "^7.1.2",
"@babel/node": "^7.0.0",
"@babel/preset-env": "^7.1.0",
"@babel/preset-react": "^7.0.0",
"@babel/register": "^7.0.0",
"babel-core": "^7.0.0-bridge.0",
"babel-jest": "^23.6.0",
"babel-loader": "^8.0.4"

And I had to install babel-core@^7.0.0-bridge.0 like it is mentioned on the Jest website.

My .babelrc:

{
  "presets": [
    "@babel/preset-env",
    "@babel/preset-react"
  ]
}

And my npm script: jest --config ./test/jest.config.json It didn't change for the Babel 7 upgrade.