Number with Largest Sum of Digits

function findLargestBySumOfDigits(arr){

    var current=0;;
    var digit=0;;
    var sum=0;
    var maxSum=0;
    var maxNum=0;

        for (var i = 0; i < arr.length; i++) {
            if ((typeof (arr[i]) !== 'number') || Math.floor(arr[i]) !== arr[i]) {
                return 'undefined';
                break;
            }
            current = arr[i];
            var currentStr = current.toString();

            for (var j = 0; j < currentStr.length; j++) {
                digit = Math.abs(current) % 10;
                current = Math.floor(current / 10);
                sum += digit;
            }
            if (sum > maxSum) {
                maxSum = sum;
                maxNum = arr[i];
            }
            sum = 0;

        }
        return maxNum;
}

console.log(findLargestBySumOfDigits([5, 10, 15, 111]));
console.log(findLargestBySumOfDigits([33, 44, -99, 0, 20]));
console.log(findLargestBySumOfDigits('hello'));
console.log(findLargestBySumOfDigits([5, 3.3]));