I was going to post the react native project for this, but it's actually pretty simple.
react-native init [projectname]
cd [projectname]
Copy the App.js from this repository into your project directory.
npm install --save rhdeck/react-native-swift-demo-module
npm install --save react-native-swift
npm install
react-native link
Done! To Test:
react-native run-ios
Get a Hell Yeah!
Check out the debugger for the console log output of the sample module doing its thing.