> Nothing random about it, automatic semicolon insertion is well defined/documented
Figured someone would say that. Yes, of course it's not random: it's a computer, it follows the same instructions every time.
What I meant, of course, is that it isn't logical. You can't guess it without having to check the spec. In bash you know that a newline is as good as a semicolon, in C you know you always need a semicolon, and in Python you know you never need it. In JS it's somewhere in between. Reading that spec, it's when the next line would have syntax that is illegal if it were a continuation... so you have to do JS simulation in your head to check if your code could, perhaps, make sense as a line continuation. So I guess you just always have to do it. I'm not saying it's a major issue and this is the one reason I don't use it, but similar to how people criticize PHP for having inconsistent function names (which is also not a bug or broken), it would have been nice if it weren't the case.
> let [3] is your scoping friend
It's not about it being possible, it's that global scoped default is just asking for abuse of the global scope. Even PHP doesn't do that, and PHP is really made for quick and dirty web development (or at least it used to be, so it supports many things that make that possible).