Does Google Apps Script support external IDEs?

Question

I am using Google Apps Script and was wondering if I could use any sort of editor outside of the one Google provides. (I purchased Sublime Text and would like to use that.)<

Answer 1

This is an answer for basic/beginner users of Intellij that are looking for code completion when writing Google App Scripts apps. Most of the answers above were helpful for getting me going, especially with Clasp. But none of them actually got Intellij to do the code complete. But this does:

Select File, Settings, Languages & Frameworks, JavaScript, Libraries.

Then on the right select Download, the scroll down to 'google-app-scripts'. (Lots of scrolling) Download and install and you're done. Almost so easy that it really shouldn't have been so hard to find.