ES6 was released 16 years ago. I'm building on top of ES6 like it's rock solid, and so far I haven't been disappointed. After ES6 the langdev process changed materially, and it now rewards introducing language features that are, in my view, half-baked. I have had to take over parts of the work of the standards committee to be able to do this project at all.
I had to reinvent iteration to get both perf and abstraction at the same time: https://docs.bablr.org/architecture/spacetime
I also had to create records and deep freezing: https://es.discourse.group/t/proposal-records-a-new-one/2546...