But you don't have to do either of those things. There's a third way, with functions and bare objects. I'm not sure that's what GP meant, but a lot of the JS I've written (which tends to be for the browser, mostly vanilla, and quick-and-dirty, to be fair) never touches classes or prototypes. The JSON data being produced/consumed is just a bag of fields, the operations on the document are just top-level functions, events get handled in callback closures, responses to HTTP requests get handled with promises, etc. Sprinkle in some JSDoc comments and you even get fairly workable autocomplete suggestions. Of course, the web APIs are built on prototypes/classes, so it's not like they're totally absent. But with things like data attributes, querySelector, and HTML templates, the usual needs for my own code to be OOP (or even structs-with-methods a la Go/Rust) just don't emerge that much.

Yeah, I would do a lot with plain objects, and using closures and iifes to do encapsulation and what-not. It was ugly and a bit of a pain, but once you learned how it all worked it made sense and was doable. I felt that classes were a bit of a bolt-on that violated my own internal understanding of how JavaScript worked, but by that point I was moving on to other stuff so never really got used to it.