It"s the very strange mix of very bad ideas and very good ideas that's baffling. Some other languages are homogeneously bad (php) but provides less suprises than js, because of their regularity. js is bipolar/schizophreniac.
JS is special because it has to be backwards-compatible.
It basically contains its entire history, from a PHP-like hack job that started it to the very elegant ES6/7. It's probably one of the few languages that expose their whole fossil record.
Yes. We tend to forget javascript was the first mainstream language (no, CommonLisp is not mainstream) proposing lambdas & closures, for instance. In the 1990's, that was quite amazing. And, on the other hand, they couldn't implement the 'this' keyword correctly, among other trivial mistakes.
