I concur about Javascript, but I don't think it's true for Typescript. Typescript is a remarkably powerful typing language.

It's still got some baggage left over from Javascript, to be sure. But the typing is genuinely very good, and more than sufficient for "basic comprehensive abstractions".

JSX is just Javascript with syntactic sugar for HTML. It's not really intended as a general-purpose language. TSX is a fine language, but I wouldn't use it for "basic comprehensive abstractions".