Coders have misconstrued fizzbuzz into a whiteboard pissing contest because they want a binary yes/no interview framework... But that causes them to miss the forest for all the trees.
So at the end of the day, it's not really about experience, it's the attitude.
I only know "Promises" because I saw that on HN recently. However the concept behind JavaScript promises is one that I've seen before (I first saw it buried in a sideways way inside of http://search.cpan.org/~karasik/IO-Lambda/) and the name "promises" already has a spot reserved in my brain for their use in infinite streams. Therefore if someone mentions JavaScript promises to me again in 6 months I'll draw a blank.
There are some code samples linked in the articles in http://elem.com/~btilly/ab-testing-multiple-looks/index.html if you want to look. I wasn't writing that code for anyone except myself, so it isn't particularly pretty. (It did get the job done though.)
I don't know how to judge that comment.
It is true that if you take anyone who is competent and ask them to teach you something that they learned in the last year, they should be able to come up with something. If not, then you've likely got "1 year of experience, 15 times". However my experience of people who think that they can judge people in the way you are judging them will judge by asking random questions about random technologies. Which is basically rolling the dice - if the person is exploring the same things that you are, then they get the gold star, otherwise you are convinced that they don't.
Let me give you a concrete example. You ask me what my primary language is. Perl, but right now I'm doing a bit of work in C++. Now you know that I'm a dinosaur because I'm using archaic languages. But don't notice that I have actually programmed in a host of other languages, and at this point learning the latest language is not going to help me be better at what I do. If I need it, I'll learn it then.
You ask me something about promises and jQuery and I draw a blank. I never liked front end work, and I've been working on back end stuff for the last decade. Boom, I'm a dinosaur in your books. But ask me what I'm reading, and you'll find out that I'm working through a book on hierarchical Bayesian modeling. I've also been doing some thinking about how people fail to understand the statistics behind A/B tests, and have been working on a series of articles that a lot of people seem to like.
In short, it is likely that you would quickly judge me poorly. Yet I believe that this reflects more on your judgement than my abilities.