roman-numerals-first

const conversions = {
  0: '', 1: 'I', 2: 'II', 3: 'III', 4: 'IV', 5: 'V', 
  6: 'VI', 7: 'VII', 8: 'VIII', 9: 'IX', 10: 'X',
  20: 'XX', 30: 'XXX', 40: 'XL', 50: 'L', 60: 'LX',
  70: 'LXX', 80: 'LXXX', 90: 'XC', 100: 'C', 200: 'CC',
  300: 'CCC', 400: 'CD', 500: 'D', 600: 'DC', 700: 'DCC',
  800: 'DCCC', 900: 'CM', 1000: 'M', 2000: 'MM', 3000: 'MMM'
};

function convertToRoman(num) {
  const numArray = String(num).split('');
  const len = numArray.length;
  const ones = conversions[Number(numArray[numArray.length - 1])];
  let thousands, hundreds, tens;
  let ans = '';
  
  switch(len) {
    case 1:
      ans = ones;
      break;
    case 2:
      tens = numArray[0] + '0';
      ans = conversions[Number(tens)] + ones;
      break;
    case 3:
      hundreds = numArray[0] + '00';
      tens = numArray[1] + '0';
      ans = conversions[Number(hundreds)] + conversions[Number(tens)] + ones;
      break;
    case 4:
      thousands = numArray[0] + '000';
      hundreds = numArray[1] + '00';
      tens = numArray[2] + '0';
      ans = conversions[Number(thousands)] + conversions[Number(hundreds)] + conversions[Number(tens)] + ones;
      break;
    default:
      ans = 'Cannot find roman numeral equivelent';
      break;
  }
  
  return ans;
}