From time to time I’ve seen good things about Expo fly by on the Twitters, which piqued my interest:
Expo apps are React Native apps which contain the Expo SDK. The SDK is a native-and-JS library which provides access to the device’s system functionality (things like the camera, contacts, local storage, and other hardware). That means you don’t need to use Xcode or Android Studio, or write any native code, and it also makes your pure-JS project very portable because it can run in any native environment containing the Expo SDK.
Also comes with an online editor, named Expo Snack, that can run code immediately on your phone (after scanning a QR Code with the Expo App)