Avoid Barrel File Imports Import directly from source files instead of barrel files to avoid loading thousands of unused modules. Barrel files are entry points that re-export multiple modules (e.g., that does ). Popular icon and component libraries can have up to 10,000 re-exports in their entry file. For many React packages, it takes 200-800ms just to import them , affecting both development speed and production cold starts. Why tree-shaking doesn't help: When a library is marked as external (not bundled), the bundler can't optimize it. If you bundle it to enable tree-shaking, builds become…