VS Code is not an IDE in the classic sense of what IDE is - integrated development environment. It's a text editor with some debugging extensions. I don't think it is even comparable to Visual Studio at all.
That line is getting really blurry with both Atom and VSCode. Haven't used VSCode, but the only feature I recall missing in Atom right now is refactoring; and to be fair, last time I used a real IDE (XCode), I couldn't refactor there either.
For me, refactoring is something that is nice to have, certainly, but not what defines an IDE. The debugging and development facilities are what matter most.
A lot of that is available in "text editors" like Atom (and I assume VSCode). Of course, it depends on if someone wrote a plugin for your language of choice.
IMO it qualifies as an IDE for Typescript, and borderline with Javascript — slightly better than WebStorm in the former case and slightly worse in the latter — but not so much other languages.