// the find
callstack/react-native-bundle-visualizer
See what packages are increasing your react-native bundle size 📦
A thin CLI wrapper that runs Metro bundler in production mode, grabs the source map, then pipes it through source-map-explorer to render a treemap of your React Native bundle. One command, opens a browser, shows you which packages are eating your bytes. Useful for any RN or Expo project where you suspect an import is ballooning the bundle.
Zero-config npx invocation — no install required, it just works on a fresh project. Expo support is explicit and versioned, not an afterthought. The `--format json` option means you can integrate the output into CI size-budget checks. Maintained by Callstack, who actually ship large RN apps, so the Metro-specific edge cases get attention.
It's essentially a two-line script that calls Metro then source-map-explorer — there's no original analysis logic here, so you're just getting a thin shell around existing tools. The unmapped bytes problem (often 20–40% of the bundle) means the treemap can be misleading for bundles with heavy babel transforms or hermes bytecode. Expo Atlas is a more capable alternative for Expo users specifically, with per-module dependency graphs rather than just size breakdowns. Single JS file in src/ with no tests — there's a CI badge but it's testing the npm publish flow, not the actual visualization logic.