The input nums is supposed to be an array of unique integers ranging from 1 to mums.length (inclusive), However, there's a mistake one of the numbers in the arrays duplicated, which means another number is missing Find and return the sum of the duplicated number and the missing number. Example: in the array [4, 3, 3, 11.3is present twice and 2 is missing so 312-5 should be returned

Script
function sumMissingAndDuplicate(nums) {
  let sum = 0;
  for (let i = 0; i < nums.length; i++) {
    sum += nums[i];
  }
  let arraySum = nums.length * (nums.length + 1) / 2;
  let duplicate = sum - arraySum;
  let missing = duplicate - (sum - duplicate)
  return (duplicate + missing)
}
sumMissingAndDuplicate([4, 3, 3, 11])