Tree Shaking React Native Apps
Article Summary
Klarna Engineering borrowed a web optimization technique and cut their React Native app startup time by 20%. Here's how tree shaking made the difference.
The Klarna team applied tree shaking (dead-code elimination) to their React Native app, tackling technical challenges around module systems and syntax compatibility. This detailed implementation guide shows how web bundling techniques can dramatically improve mobile performance.
Key Takeaways
- Tree shaking works best with ES modules, not CommonJS (static analysis matters)
- Critical JavaScript chunk reduced by 46%, overall bundle down 14%
- Samsung Galaxy S9 startup improved from 2.8s to 2.2s in production
- Build times increased 30% but user experience gains justified the tradeoff
- TypeScript's isolatedModules flag fixed invalid re-export issues
Critical Insight
By implementing tree shaking in React Native, Klarna achieved a 20% median startup improvement and 46% smaller critical bundle, proving web optimization techniques translate to mobile.
