Javascript can be written both in a functional and an oo style, it doesn’t prescribe one over the other. The way inheritance works (prototype based) might be a source of confusion, because even though there is a class based syntax since 2015, it still has a prototype chain under the hood. Also the binding of the this pointer can work in unexpected ways. And things like scope and hoisting of variables are a bit different. Also there is no overloading of methods. It pays off quickly to read about the basic mechanics of the language if you want to do something with it.

I’m working in a company where many developers have a strong Java background, the company adopted Typescript/Angular a few years ago for new projects and it got adopted by colleagues with long tenures quickly, the syntax similarities are so close that in my eyes it is more problematic when some expectations are translated over that just don’t hold, than that the colleagues struggeling with language itself, more difficult might be that standard library does not translate over in the same way the language primitives do.