It might interest you to know JS has real private fields, formally introduced in ES2022. [1]
[1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
[1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
Not to mention the fact that GP's issue only matters if you're using classes. You can define module-level variables and simply not export them and they are 100% private. Or, they can just define the variable inside of a function and protect it by a closure. I can't imagine writing multiple paragraphs of complaints about a language that I don't actually understand how to use.
However I don't really want to talk to you. You are rude.