Vitali Zaidman
b37101486b
Summary: Pull Request resolved: https://github.com/facebook/react-native/pull/46295 X-link: https://github.com/facebook/metro/pull/1343 Updated all **babel** packages in all `package.json` across the repo and ran `npx yarn-deduplicate yarn.lock --scopes babel`. Afterwards, fixed the following issues appearing as a result of that (squashed the following initially separate diffs to make this packages update work atomically): ### (D61336392) updated jest snapshot tests failing ### (D61336393) updated babel types and corrected typings accordingly The latest babel 7 introduces the following features we need to adjust our types to: * `JSXNamespacedName` is removed from valid `CallExpression` args ([PR](https://github.com/babel/babel/pull/16421)) * `JSXNamespacedName` is used for namespaced XML properties in things like `<div namespace:name="value">`, but `fn(namespace:name)` doesn't make any sense. * Dynamic imports are enabled behind a new flag `createImportExpressions` ([PR](https://github.com/babel/babel/pull/15682)), introducing calls such as `import(foo, options)`. These complicate the expected values passed to `import` to be more than just strings. * Since these are behind a flag that is not expected to be enabled, we can throw an error for now and whoever uses it can add a support to it if needed later. ### Added a new metro ENV ignore `BROWSERSLIST_ROOT_PATH` is set to `""` explicitly in `xplat/js/BUCK` and then ignored in `js/tools/metro-buck-transform-worker/src/EnvVarAllowList.js` Reviewed By: robhogan Differential Revision: D61543660 fbshipit-source-id: abbcab72642cf6dc03eed5142eb78dbcc7f63a86
@react-native/babel-preset
Babel presets for React Native applications. React Native itself uses this Babel preset by default when transforming your app's source code.
If you wish to use a custom Babel configuration by writing a babel.config.js file in your project's root directory, you must specify all the plugins necessary to transform your code. React Native does not apply its default Babel configuration in this case. So, to make your life easier, you can use this preset to get the default configuration and then specify more plugins that run before it.
Usage
As mentioned above, you only need to use this preset if you are writing a custom babel.config.js file.
Installation
Install @react-native/babel-preset in your app:
with npm:
npm i @react-native/babel-preset --save-dev
or with yarn:
yarn add -D @react-native/babel-preset
Configuring Babel
Then, create a file called babel.config.js in your project's root directory. The existence of this babel.config.js file will tell React Native to use your custom Babel configuration instead of its own. Then load this preset:
{
"presets": ["module:@react-native/babel-preset"]
}
You can further customize your Babel configuration by specifying plugins and other options. See Babel's babel.config.js documentation to learn more.
Help and Support
If you get stuck configuring Babel, please ask a question on Stack Overflow or find a consultant for help. If you discover a bug, please open up an issue.