After ready about Popcorntime app, I've got interested in building desktop applications that are based on javascript and nodejs(?). But reading the code didn't really give away any tips on how to start.

I don't really know where to start, So I would like to get some pointers where to look, what to read, what to watch etc.

Are there any frameworks? How is the window built? How does the app communicate with the OS?

Examples: https://github.com/popcorn-time/popcorn-app https://github.com/adobe/brackets

Thank you.