JS sets are plenty useful. Sometimes you want reference equality for objects (though letting programmers choose would be ideal). As far as the pace, I think th

JS sets are plenty useful. Sometimes you want reference equality for objects (though letting programmers choose would be ideal). As far as the pace, I think they do it about right. JS has hard requirements to be backwards compatible and has several canonical implementations, so adding new features should only be done after careful consideration. Letting users add features themselves and ensuring they have staying power and wide adoption is a good test.