babel-jest

Usage

If you are already using jest-cli, just add babel-jest and it will automatically compile JavaScript code using babel.

npm install --save-dev babel-jest babel-core

Note: If you are using babel version 7 you have to install babel-jest with
npm install --save-dev babel-jest babel-core@^7.0.0-0 @babel/core

If you would like to write your own preprocessor, uninstall and delete babel-jest and set the config.transform option to your preprocessor.

Note: this step is only required if you are using babel-jest with additional code preprocessors.

To explicitly define babel-jest as a transformer for your JavaScript code, map .js files to the babel-jest module.

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