var vs let

var_let.js

var sum  = 0;
var length = 1000000000;
var i = 0;
// let j = 0;
console.time("let time");
    for(let j = 0;j<length;j++){
        sum += j;
    }
console.timeEnd("let time");
console.info("let total ", sum)

console.log("-------------------------------")

sum  = 0;

console.time("var time");
    for(i = 0;i<length;i++){
        sum += i;
    }
console.timeEnd("var time");
console.info("var total ", sum)