Being a java-ist, I could not consider to learn JS without a proper type system, and a proper IDE (with autocompletion, static analysis & refactoring facilities). TypeScript & VSCode/IntelliJ save my day now. More advanced programming paradigms (a la Haskell) are nowadays almost doable in the JS ecosystem. So yes, I would consider that JS has matured as a platform.

I still have no clue about frontend web frameworks yet.