number to roman

number_to_roman.js

var roman = {
  M: 1000,
  CM: 900,
  D: 500,
  CD: 400,
  C: 100,
  XC: 90,
  L: 50,
  XL: 40,
  X: 10,
  IX: 9,
  V: 5,
  IV: 4,
  I: 1
};

function convertToRoman(num) {
  if (isNaN(num)) return  NaN;

  var str = '';
  
  for (var i in roman) {
    var repeat = Math.floor(num / roman[i]);

    num -= repeat * roman[i];
    str += i.repeat(repeat);
  }

  return str;
}

console.log(convertToRoman(3));
console.log(convertToRoman(4));
console.log(convertToRoman(9));
console.log(convertToRoman(58));
console.log(convertToRoman(1994));