| # babel-jest | |
| [Babel](https://github.com/babel/babel) [jest](https://github.com/jestjs/jest) plugin | |
| ## Usage | |
| If you are already using `jest-cli`, add `babel-jest` and it will automatically compile JavaScript code using Babel. | |
| ```bash | |
| yarn add --dev babel-jest @babel/core | |
| ``` | |
| If you would like to write your own preprocessor, uninstall and delete babel-jest and set the [config.transform](https://jestjs.io/docs/configuration#transform-object-string-string) option to your preprocessor. | |
| ## Setup | |
| _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. Typescript files are also supported. | |
| ```json | |
| "transform": { | |
| "\\.[jt]sx?$": "babel-jest" | |
| }, | |
| ``` | |