Some time ago on the I've been asked about dead zone exception in javascript, I didn't know what it is so started googling.

Ok, so there is no any kind of Exception called DeadZoneException like java's NullPointerException. Ok so maybe the guy who ask, was about Temporal Dead Zone, so I don't know this either, let's check what that is.

As stackoverflow shows:

console.log(aVar); // undefined
console.log(aLet); // causes ReferenceError: aLet is not defined
var aVar = 1;
let aLet = 2;

So, as spec says let and const are hoisted but if you're accessing them before declaration you won't get undefined as with usual var but you'll get RefferenceError.  Nice.

So, TIL what is Temporal Dead Zone