Number with Largest Sum of Digits

/* Write a JavaScript function findLargestBySumOfDigits(arr) that accepts as a parameter an array of numbers
or/and strings and returns the element with the largest sum of its digits. The function should take
a variable number of arguments. It should return undefined when 0 arguments are passed or when some
of the arguments is not an integer number. Write a JS program largestSumOfDigits.js that invokes your function
with the sample input data below and prints its output at the console. */

"use strict";

function findLargestBySumOfDigits(arr) {
    if (!arr.length) {
        return undefined;
    }

    for (var i = 0; i < arr.length; i += 1) {
        if (arr[i] == Number(parseInt(arr[i])) && arr[i] % 1 === 0) arr[i] = parseInt(arr[i]);
        else return undefined;
    }

    var maxSum = 0;
    var indexMax = 0;
    for (i = 0; i < arr.length; i += 1) {
        var number = Math.abs(arr[i]);
        var sum = 0;
        do {
            sum += number % 10;
            number = parseInt(number / 10);
        } while (number);

        if (sum > maxSum) {
            indexMax = i;
            maxSum = sum;
        }
    }

    return arr[indexMax];
}

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]));
console.log(findLargestBySumOfDigits(['32', '149', '-96', '428']));
console.log(findLargestBySumOfDigits([]));