[robinduckett]

I like `let`. It means you have to be implicit and actually be aware of what you're doing.

[ajanuary]

That part of the article isn't particularly clear. The intended behavior of let is great. The unintended behavior - that it can cause typeof to fail - is bad.

[taf2]

It seems to me typeof in the described case should return undefined.

[ajanuary]

typeof is never being invoked, so it can't return anything.

The rules of let are that any reference to the variable before the let declaration (the "temporal dead zone"), it's a reference error. So the reference error is being thrown before typeof is invoked.