babel-jest
Advanced tools
[Babel](https://github.com/babel/babel) [jest](https://github.com/facebook/jest) plugin
Package description
The babel-jest package is a Jest plugin that makes it easy to use Babel to transform your JavaScript tests. It automatically hooks Babel into Jest and compiles files before running them, allowing you to use the latest JavaScript features and syntax in your test files.
Transforming test files with Babel
This configuration in Jest's setup file tells Jest to use babel-jest for transforming any files that match the regex pattern (in this case, any JavaScript files) before running the tests.
module.exports = {
transform: {
'^.+\\.js$': 'babel-jest'
}
};Using modern JavaScript syntax in tests
With babel-jest, you can write tests using modern JavaScript features like async/await without worrying about compatibility issues.
test('async/await works', async () => {
const data = await fetchData();
expect(data).toBe('expected data');
});Custom Babel configuration
babel-jest allows you to specify a custom Babel configuration to tailor the transformation process to your project's needs.
{
'presets': [['@babel/preset-env', { 'targets': { 'node': 'current' } }]],
'plugins': ['@babel/plugin-proposal-class-properties']
}ts-jest is a TypeScript preprocessor with source map support for Jest. It allows you to use Jest to test projects written in TypeScript. It is similar to babel-jest but specifically tailored for TypeScript rather than general Babel transformations.
jest-transform-stub is a package that allows you to stub out resources, like images or styles, during testing with Jest. It is similar to babel-jest in that it transforms assets, but it focuses on non-JavaScript assets instead of JavaScript code.
jest-vue-preprocessor is a preprocessor for Jest to handle .vue files, allowing you to test Vue components. It is similar to babel-jest in the sense that it preprocesses files for testing, but it is specifically designed for Vue components.
Changelog
25.2.0
[jest-config] Support ESM config files with .js extension (#9573).[jest-runtime] Override module.createRequire to return a Jest-compatible require function (#9469)[jest-haste-map] [BREAKING] Remove mapper option (#9581)[*] Support array of paths for moduleNameMapper aliases (#9465)[jest-reporters] Adds ability to pass options to the istanbul-reporter through coverageReporters (#9572)[jest-runtime] Require stack when a module cannot be resolved (#9681)[jest-transform] writeCacheFile no longer calls fsync (#9695)[expect] Handle readonly properties correctly (#9575)[jest-cli] Set coverageProvider correctly when provided in config (#9562)[jest-cli] Allow specifying .cjs and .mjs config files by --config CLI option (#9578)[jest-cli] Update yargs to fix CLI flag overriding (#9519)[jest-config] Treat setupFilesAfterEnv like setupFiles when normalizing configs against presets (#9495)[jest-config] Support .mjs config files on Windows as well (#9558)[jest-config] Verify rootDir and all roots are directories (#9569)[jest-config] Ensure pattern of replacePosixSep is a string (#9546)[jest-haste-map] Fix crash on unix based systems without find (#9579)[jest-jasmine2] Fix --testNamePattern matching with concurrent tests (#9090)[jest-matcher-utils] Fix diff highlight of symbol-keyed object. (#9499)[@jest/reporters] Notifications should be fire&forget rather than having a timeout (#9567)[jest-resolve] Fix module identity preservation with symlinks and browser field resolution (#9511)[jest-resolve] Do not confuse directories with files (#8912)[jest-resolve] moduleNameMapper should take precedence over Node core modules (#9563)[jest-runtime] Reset isolateModules if it fails (#9541)[jest-runtime] Yarn PnP errors displayed to the user (#9681)[jest-snapshot] Downgrade semver to v6 to support node 8 (#9451)[jest-snapshot] Properly indent new snapshots in the presences of existing ones (#9523)[jest-transform] Correct sourcemap behavior for transformed and instrumented code (#9460)[jest-transform] Allow instrumentation of transformed files with weird file extensions (#9589)[@jest/types] Make ConfigGlobals an interface to allow for declaration merging. (#9570)[pretty-format] Export OldPlugin type (#9491)[docs] Warn about unexpected behavior / bug of node-notifier when using the notify options.[docs] Grammatical corrections to Async docs page. (#9679)[jest-resolver] Use resolve package to implement custom module resolution (#9520)[jest-runtime] Move execution of setupFiles to jest-runner (#9596)[jest-runtime] Update anchor link in helpers (#9616)[@jest/reporters] Remove unused dependencies and type exports (#9462)[website] Update pictures of reports when matchers fail (#9214)[jest-haste-map] Reduce number of lstat calls in node crawler (#9514)Readme
Make the following changes to package.json:
{
"devDependencies": {
"babel-jest": "*",
"jest-cli": "*"
},
"scripts": {
"test": "jest"
},
"jest": {
"scriptPreprocessor": "<rootDir>/node_modules/babel-jest",
"testFileExtensions": ["es6", "js"],
"moduleFileExtensions": ["js", "json", "es6"]
}
}
And run:
$ npm install
And you're good to go!
By default, babel-jest will use Babel's default stage (stage 2). If you'd like to use one of the other stages, set the environment variable:
BABEL_JEST_STAGE
And then you can modify the test command in package.json like so:
{
// Normal package.json stuff
"scripts": {
"test": "BABEL_JEST_STAGE=0 jest"
},
// Normal package.json stuff
}
FAQs
Jest plugin to use babel for transformation.
The npm package babel-jest receives a total of 19,451,279 weekly downloads. As such, babel-jest popularity was classified as popular.
We found that babel-jest demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 3 open source maintainers collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
Security News
GitHub is combatting a new spam campaign that exploits issues with links to malicious downloads, highlighting the need for better moderation tools to protect open-source maintainers' time and security.
Security News
uv, Python's new package manager, offers a faster and more efficient alternative to pip with features that simplify tooling, manage Python versions, and streamline development workflows.
Research
Security News
Socket researchers have uncovered 3.7 million fake GitHub stars, highlighting a growing threat linked to scams, fraud, and malware, with these campaigns rapidly increasing over the last six months.