Building framework with shared code on Android and iOS using React Native

Everybody heard that with React Native you can build mobile apps and share most of the code. But not everybody knows that this is also true for building frameworks (even with no UI), i.e. self-contained libraries that can be integrated into another library or app, whether it is React Native app or not. 

 

I will show when and why this might be a perfect case for you (and when not a good idea at all). How in the long term you can save time, code and roll out new features faster. What must be tweaked in "react-native init App" template project for painless start. Benchmarks, problems, challenges, and transformations that my team experienced while migrating from separate Android, iOS and Web codebases into shared one.