I am creating a multi-mobile (iOS/Android) app with React Native.
The app needs to embed & launch a Unity game.
It will need to send information to the game, and also receive information from the game. A function passing a JSON string would be sufficient.
Six years ago I embedded native iOS code within a Unity app and it was rather a dark art.
What is the state of play in 2018?
Presumably it is going to involve separate iOS and Android codebases and a ReactNative component to wrap these, providing a single JavaScript interface. At the Unity end, I'm not sure if it will require separate per-platform coding.