알고리즘 - 로마자 변환

const s = "IX";
function romanToNum(s) {
  let newArr = s.split("");
  let answer = 0;
  let divider = 0;
  let formatted = {
    I: 1,
    V: 5,
    X: 10,
    L: 50,
    C: 100,
    D: 500,
    M: 1000,
  };
  answer += formatted[newArr[0]];
  
  for (let i = 1; i < s.length; i++) {
    if (formatted[newArr[i]] % 5 === 0) {
      if (formatted[newArr[i - 1]] < formatted[newArr[i]]) {
        divider = formatted[newArr[i]] / 5;
        if (divider === Math.pow(10, formatted[newArr[i]].toString().length-1)) {
          answer += formatted[newArr[i]] - divider * 2;
        } else {
          answer += formatted[newArr[i]] - divider;
        }
      } else {
        answer += formatted[newArr[i]];
      }
    } else {
      answer += formatted[newArr[i]]
    }
  }
  return answer;
}

romanToNum(s);