Of course. But within the JavaScript community, it has taken on specific meaning: no 3rd party libraries at runtime. For "vanilla js," I can still have compile

Of course. But within the JavaScript community, it has taken on specific meaning: no 3rd party libraries at runtime. For "vanilla js," I can still have compilers, type checking, advanced ECMAScript 2019 features, local storage, webgl, etc. Without that understanding, you could qualify something as "vanilla js" in lots of different ways. If someone said "vanilla c++," they might mean c++ without the recent language features, or they could mean the latest language spec but no standard library. Maybe it's still okay to link OpenGL but not okay to use a desktop GUI framework? Maybe OS frameworks are okay but nothing more? There's no communal understanding there that I'm aware of.