| 1 | # babel-jest
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| 2 |
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| 3 | [Babel](https://github.com/babel/babel) [jest](https://github.com/facebook/jest) plugin
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| 4 |
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| 5 | ## Usage
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| 6 |
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| 7 | If you are already using `jest-cli`, just add `babel-jest` and it will automatically compile JavaScript code using Babel.
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| 8 |
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| 9 | ```bash
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| 10 | yarn add --dev babel-jest @babel/core
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| 11 | ```
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| 12 |
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| 13 | 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.
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| 14 |
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| 15 | ## Setup
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| 16 |
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| 17 | _Note: this step is only required if you are using `babel-jest` with additional code preprocessors._
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| 18 |
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| 19 | To explicitly define `babel-jest` as a transformer for your JavaScript code, map _.js_ files to the `babel-jest` module.
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| 20 |
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| 21 | ```json
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| 22 | "transform": {
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| 23 | "^.+\\.jsx?$": "babel-jest"
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| 24 | },
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| 25 | ```
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