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Faster Metro startup Metro is >3x faster to cold start, with bigger speedups on larger projects - great news for monorepos and CI builds. This was achieved by deferring source hashing to only read files actually bundled, greatly reducing IO with negligible impact on build speed.

Faster Android startup The startup time of all Android apps has been improved by skipping the compression step for the JavaScript bundle. For the Discord mobile app, the Margelo team measured a 12% time-to-interactive (TTI) improvement, which made the app start 400ms faster on a Samsung A14.

8/4/25, 1:22 pm0 reposts3 likes

github.comGitHub - react-native-community/javascriptcore: JavaScriptCore for React NativeJavaScriptCore for React Native . Contribute to react-native-community/javascriptcore development by creating an account on GitHub.

JSC is moving to a community package Starting with React Native 0.79, JavaScriptCore (JSC) is moving to `@react-native-community/javascriptcore` This allows for more frequent updates and latest features, while reducing React Native's API surface. Don't worry — this won't affect Hermes users!

Swift-compatible Native Module registration We've improved the registration mechanism for Native Modules on iOS. Starting from React Native 0.79, you only need to add 2 lines to package.json to register your Native Module. This works also with pure C++ modules and apps written in Swift.

Metro Package Exports support by default Metro now respects package.json exports and imports fields by default, with improved handling of import/require conditions. Let us know of any issues and use resolver.unstable_enablePackageExports = false in your Metro config to opt-out.