Metro: The JavaScript Bundler for React Native
Metro bundles your React Native app's JavaScript, finding all modules, transpiling them for the device, and merging them into one file. It's what powers `npx react-native start`.
Metro is React Native's JavaScript bundler, acting like a compiler for your app's code. It takes your entry file, resolves all dependencies, transforms each module into platform-compatible code, and serializes them into a single JS bundle. You see it at work every time you run `npx react-native start`. The main footgun is treating it as a black box; not understanding the distinct Resolution, Transformation, and Serialization stages makes it difficult to diagnose cache problems or slow build times.
Read the original → metrobundler.dev
- #react native
- #javascript
- #bundler
- #tooling
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