Integer to Roman.js

// Runtime: 214 ms (Top 38.09%) | Memory: 46.7 MB (Top 91.29%)

var intToRoman = function(num) {
    let res = "";
  while (num > 0) {
    if (num >= 1000) {
      res += "M";
      num -= 1000;
    }else if (num >= 900) {
      res += "CM";
      num -= 900;
    }else if (num >= 500) {
      res += "D";
      num -= 500;
    }else if (num >= 400) {
      res += "CD";
      num -= 400;
    }else if (num >= 100) {
      res += "C";
      num -= 100;
    }else if (num >= 90) {
      res += "XC";
      num -= 90;
    }else if (num >= 50) {
      res += "L";
      num -= 50;
    }else if (num >= 40) {
      res += "XL";
      num -= 40;
    }else if (num >= 10) {
      res += "X";
      num -= 10;
    }else if (num >= 9) {
      res += "IX";
      num -= 9;
    }else if (num >= 5) {
      res += "V";
      num -= 5;
    }else if (num >= 4) {
      res += "IV";
      num -= 4;
    }else if (num >= 1) {
      res += "I";
      num -= 1;
    }
  }
    return res;
};