Question: I'm looking to use React Native for app development. Since it is free and an open source, cross-platform environment. The question is: what IDE can I use to write and build and do everything in it?
Appreciate the help.

Answer: 
sublime with [Babel syntax highlighting](https://github.com/babel/babel-sublime). :)
I personally use **IntelliJ IDEA Ultimate Edition** it's Excellent try it.

But officially **Nuclide** but it still has not proper support for windows.