how to add the value of each array with - instead of , javascript

Question

New to JavaScript. below is my code, below that is what the algorithm is suppose to accomplish

function creditSum(arr) {
    var num_of_elements = parseInt(arr)
    array = arr.toString().split()
    array = array.map(Number)
    var sum_of_array = 0 
    for (var i = 0; i < num_of_elements; i++){
        sum_of_array += array[i]
    }

    return sum_of_array 
}
console.log(creditSum(['4916-2600-1804-0530', '4779-252888-3972', '4252-278893-7978', '4556-4242-9283-2260']))

For this challenge, we are interested in finding the credit card number whose digits sum to the largest number. If more than one has the same largest sum of digits, we want the last one in the list with that sum. Write a single function that takes one argument. That argument will be an array of credit card numbers. Assume the array can have any number of credit card numbers and each one is a string of digits and dashes. Your function should return the credit card number that has the largest sum of digits.

Here is a sample array of credit card numbers:

['4916-2600-1804-0530', '4779-252888-3972', '4252-278893-7978', '4556-4242-9283-2260'] 

In the sample array above, the digits add up to 49, 81, 81, and 64 respectively. Since there are two which have the same sum, the function should return the last one with that sum, in this case '4252-278893-7978'

Answer 1

Primitive way in doing this. Just for the sake of learning. I hope this gives you a clear understanding.

function creditSum(arr) {
    var sum = [], current = 0, last = 0, w = 0;

    //remove the dashed from the array item
    for(var i = 0; i < arr.length; i++){
    	var newarr = arr[i].toString().split('-');
    	var x = newarr.length;
        var s = 0;

        //loop in from the new array of item after the split
        for(var y = 0; y < x ; y++){
            var ss = 0;
            
            //get the sum of each digit
            for(var z = 0 ; z < newarr[y].length; z++){
            	ss += parseInt(newarr[y][z]);
            }
            s += parseInt(ss);
        }
        
        //push it inside an array of sum
        sum.push(s);
    }
    
    //check highest sum
    for(var d = 0; d < sum.length; d++){
    	if(d == 0) { last = sum[0] };
        current = sum[d];
        if(last <= current){
            w = d;
            last = current;
        }
        
    }
    
    return arr[w] 
}
document.body.innerHTML = (creditSum(['4916-2600-1804-0530', '4779-252888-3972', '4252-278893-7978', '4556-4242-9283-2260']));

Answer 2

I think that this should do it:

function creditSum(arr) {
  const resultIndex = arr
   .map(x => x
     .split('')
     .map(x => parseInt(x))
     .filter(x => !isNaN(x))
     .reduce((total, current) => total + current, 0)
   )
   .map((total, idx) => ({ idx, total }))
   .sort((a, b) => b.total - a.total)
   .reduce((result, current) =>
     current.total >= result.total ? current : result,
     { total: 0 }
   )
   .idx;

  return arr[resultIndex];
}