[a_lieb]

As someone who teaches JS on the side, I'm literally scared of the idea of introducing another construct called "case." Especially one that goes in the opposite place of where the "case" normally does: "switch ... case" vs. "case ... when."

JavaScript is already jam packed with subtleties and gotchas that make it hard to learn, including situations where two things have the same name or the name doesn't quite match the underlying concept: C-style "for" vs. "for ... in" vs. "for ... of," object vs. Object, Object.prototype vs. "the prototype of the object," etc. We don't need another one of those.

I'd actually like this if it used another word than "case." "choose ... when", maybe? Kinda awkward, but I bet someone could think of something better. "case" has the nice feature that it's already a reserved word, but it's not valid syntax to have a variable name right next to an open brace, so the parsers could figure it out.