I'm not sure what you mean. json.stringify {2,3,5} == '[2, 3, 5]', which is correct, isn't it? (Strictly, JSON has to always have a dictionary on the outside, but it's fairly standard to allow this.)

We'll keep thinking about this, but I don't think it's sensible to try to encode {11, ["11"]=11} at all. That's neither an array nor a dictionary, and so it doesn't have a natural JSON representation. I'm inclined to make it an error, but right now we try to be generous in attempting to encode.