"Magic comments" are pretty much universally bad. Every programming language expects that code will function the same both with and without comments.
What you might consider, which would survive minification, is to use a large string literal instead. A string, by itself on a line, is a valid JS statement (that doesn't do anything). Which is why "use strict" works, even in environments that don't support it.
oooh c'mon...
even Angular convert functions to strings and parse it...
it can be anything - but comments are good thing for programmers and now they can have another functionality added
comments role is to be transparent but why not use if you can
and if its easy, you don't need to compile it like coffee or typescript. and code is clear without a hustle.
but if you really don't want to use comments you can use object declarations instead. there is no need for using comments in clsjs but it is easier and better way I think.
of course you can disagree - that is your point of view and everything is ok.
but I will think of your suggestion about string, that is also very good idea!