Simply Array Sum

Problem from HackerRank.

Easy problem but I got confused with the index of the array and its value. I was adding i to my result variable and not ar[i].

function simpleArraySum(ar) {
    let result = 0;

    for (let i = 0; i < ar.length; i++) {
        result += ar[i];
    };

    return result;
}

function simpleArraySum(ar) {

let result = 0;

for (let i = 0; i < ar.length; i++) {

result += ar[i];

};

return result;

}