We do all kinds of screencasts - I'm editing one about ActiveAdmin on Rails right now, and we also have many other formats (.NET, some Rails) - not all just Javascript.

That said - Destroy All Screencasts is great (https://www.destroyallsoftware.com/screencasts), and PeepCode has terrific Play by Play stuff with Gary Bernhardt which I can't recommend enough: https://peepcode.com/products/play-by-play-bernhardt.

He also has Ryan Singer and Yehuda Katz doing their thing... great stuff.