How do I Save Json into specific folder at Runtime ?

Hey!

I'm working on a Level Editor right now, It's working pretty well but I'm stuck when I want to save all my data level into specific folder, I really don't know how to do that.

I know that it's possible to save to local storage, but it's not what I want.

Is it possible to save a JSON file and chose where?

Thanks in advance!

Edit : Probably working with NWJS object!

But is it possible to use it in editor mode? It would be better for beta testing to not having to build every time...