Nadya, whether or not that's the best thing to test for is beside the point. All I'm saying is that, in my view, a professional Javascript developer should know those things. And apparently, a lot of people on HN disagree with me.
What you test on is almost as important as how you test on it. Interviews go both ways after all. I think a majority of people aren't disagreeing that a professional should know these things - but asking them to "rattle off an answer to [question]" is looked down on. It reeks of the "reverse a binary tree" or "implement [some sorting algorithm]" type of questions.
I consider myself a Javascript professional (in so much that I am paid primarily for the Javascript work I do) and I had no issue knowing the answer to the three items listed. If I was asked to rattle them off the top of my head as some sort of Fizzbuzz Filter equivalent - I'd thank you for your time and leave the interview.
I agree people should know the answers - which (as you've pointed out) is the point you're trying to get across. But how you share that point, much like which questions you ask, is important.
And it still amazes me that this position seems to be controversial here on HN. There are people who have expressed unequivocal agreement, to be sure, but a significant number seem to see that stuff as obscure arcana that a developer would not typically need to know.