Pluginable cross-platform software design for react & react native
1 - As far as I know there are few of them, like React Universal UI
2 - With the above UI Kit, the distinction on how components are built (imports remain the same) is done at runtime in the boilerplate:
Web (React)
$ ruui devIOS (React Native)
$ react-native run-iosAndroid (React Native)
$ react-native run-androidIf you want you component to be imported at runtime, well, this is possible for sure in web env (you can do it also with react-create-app, with dev server turned on and no prod static build).
For Android and IOS you'll need an additional build and subscribe your app for the review before going up again to the store (AppStore and Google Play)