Introducing Hot Reloading

React Native just solved one of mobile development's most frustrating problems: losing your app state every time you make a code change. Their new Hot Reloading feature keeps your app running while injecting updated code in real-time.

The React Native team introduced Hot Reloading to eliminate the painful cycle of navigating back through multiple screens after every code reload. Built on webpack's Hot Module Replacement (HMR) architecture, this feature preserves app state while updating code on the fly, targeting sub-1-second feedback loops even as apps scale.

Key Takeaways

• Hot Reloading injects new code at runtime without losing app state
• HMR runtime walks dependency trees to refresh only affected modules
• React components use proxies to preserve state during hot swaps
• Works with Redux stores via module.hot.accept() API
• Eliminates multi-second reload cycles for features deep in navigation flows

The technical implementation reveals clever tricks with module caching and inverse dependency trees that make this seemingly impossible feature actually work.