Just Use create-react-native-library

[alfergus0n]

Since this project seems abandoned, this is the alternative and is active

repo: https://github.com/callstack/react-native-builder-bob
npm: https://www.npmjs.com/package/create-react-native-library

or a less opinionated (highly recommended): https://github.com/brodybits/create-react-native-module
npm: https://www.npmjs.com/package/create-react-native-module