But didn’t we say the same thing about JS almost every year in the past? Only for the status quo to be obsoleted in a few months? Is the breakneck change curve slowing down finally?
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.