Square Every Digit

Welcome. In this kata, you are asked to square every digit of a number and concatenate them.

For example, if we run 9119 through the function, 811181 will come out, because 9² is 81 and 1² is 1.

Note: The function accepts an integer and returns an integer

Solution

function squareDigits(num){
  res = '';
  for (c of num.toString())
    res += String(c**2);
  return Number(res);
}