Roman Numeral Exercise

roman-numeral.js

function romanNumeral(n) {
  var result    = '',
      thousands = integerDivision(n,1000),
      hundreds  = integerDivision((n % 1000),100),
      tens      = integerDivision((n % 100),10),
      ones      = n % 10;

  result += stringTimes(thousands,'m');
  result += romanHelper(hundreds,'c','d','m');
  result += romanHelper(tens,'x','l','c');
  result += romanHelper(ones,'i','v','x');
  return result;
}

function romanHelper(n, oneChar, fiveChar, tenChar) {
  var fives = integerDivision(n,5),
      ones  = n % 5;

  if (ones == 4) {
    if (fives)
      return oneChar + tenChar;
    else
      return oneChar + fiveChar;
  } else {
    return stringTimes(fives,fiveChar) + stringTimes(ones,oneChar);
  }
}

function integerDivision(a,b) {
  return Math.floor(a/b);
}

function stringTimes(n,char) {
  var str = "";
  for(var i = 0; i < n; i++) {
    str += char;
  }
  return str;
}