roman numerals

by Gerald Gillespie

JavaScript

function convertToRoman(num) {

  var numStr = num + '';
  var numArray = numStr.split('');
  var romArray = [
    ['', 'I', 'II', 'III', 'IV', 'V', 'VI', 'VII', 'VIII', 'IX'] ,
    ['', 'X', 'XX', 'XXX', 'XL', 'L', 'LX', 'LXX', 'LXXX', 'XC'],
    ['', 'C', 'CC', 'CCC', 'CD', 'D', 'DC', 'DCC', 'DCC', 'CM'],
    ['', 'M', 'MM', 'MMM'] //4th 
  ];
  num = '';
  for(let i=0, j=numArray.length ; i< numArray.length; i++){
    
   num =  romArray[i][+numArray[--j]] + num;
  //  console.log(num);
  }

  return num;
}

console.log(
  convertToRoman(3999)
)