Breaking a React-Native application into plugable modules

React native starts by pointing at a JS bundle. This means that you would at least have to restart the app to reload the js bundle (assuming that you're reading it from a server and not from the ios device itself).

If you did have a way to update the js files on the server (through some sort of web service that updated based on things the user does) then restarting the app could theoretically reload the JS and provide new functionality to the app.