var, let, const

Var, Let, Const difference

Var

Duplicate declaration possible Scope: global, function

var first = 10;
var fitst = 20;

Let

Duplicate declaration NOT possible Scope: global, function

let second = 10;
let second = 20;   # error !

Const

Duplicate declaration NOT possible

Initialize at the time of declaration

Final

Section	Var	Let	Const
Re-declaration	O	X	X
Update	X	O	X
Scope	Global	Block	Block