React Native Version 0.70 Release
Article Summary
React Native 0.70 just made Hermes the default JavaScript engine. This marks a major turning point for performance and developer experience across both iOS and Android.
The React Native team released version 0.70 with significant improvements centered around the New Architecture. This release represents months of collaboration between Meta's Hermes and React Native teams, with contributions from 88 community contributors across 493 commits.
Key Takeaways
- Hermes now ships as default engine after extensive performance tuning
- Unified Codegen configuration in package.json replaces separate Android setup
- CMake support reduces native build config from 50+ lines to just 3
- Android auto-linking now works seamlessly with New Architecture libraries
- APK size reduced by ~220 KB through removal of duplicate dependencies
React Native 0.70 dramatically simplifies New Architecture adoption with unified tooling, default Hermes engine, and streamlined native build configuration.
About This Article
React Native library maintainers had to juggle different configuration approaches. Android required setup in build.gradle files, while iOS used something entirely different. This made it hard to migrate consistently to the New Architecture.
The React Native team added Codegen configuration directly to package.json. Now developers can define specs for both iOS and Android in one place using standardized fields like javaPackageName instead of managing separate setups.
Library maintainers can migrate to the New Architecture using the same process on both platforms. Configuration is simpler and there's less to maintain across iOS and Android.