I mean kudos to the guy for trying something new but honestly I'd expect anyone working as a developer in IT to have learned this much before calling themselves a professional. And that includes Javascript devs since so much of frontend development is event-driven anyway.
Personally I get a little fed up by just how _bad_ many frontend developers seem to be these days. I'm not tarring everyone with the same brush as I'm known some really amazing frontend devs too (though they ususally consider themselves full stack). But I've lost count of the number of Javascript developers who I've had to explain HTTP status codes and the difference between GET and POST. It feels like frontend development is a place where people go if they like the idea of coding but can't be bothered to learn how to actually programme nor any of the principles they're building their code on top of. Thankfully the topic author bucks that trend a little but even in his case the lessons he is learning are painfully basic.
By the way it's a bank holiday (long weekend) in the UK so no Mondays blues from me. :D