JS - Roman Numeral <-> Number Converter

gistfile1.txt

function romanize(num) {
  var lookup = {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},
      roman = '',
      i;
  for ( i in lookup ) {
    while ( num >= lookup[i] ) {
      roman += i;
      num -= lookup[i];
    }
  }
  return roman;
}





function deromanize( roman ) {
  var roman = roman.toUpperCase(),
      lookup = {I:1,V:5,X:10,L:50,C:100,D:500,M:1000},
      arabic = 0,
      i = roman.length;
  while (i--) {
    if ( lookup[roman[i]] < lookup[roman[i+1]] )
      arabic -= lookup[roman[i]];
    else
      arabic += lookup[roman[i]];
  }
  return arabic;
  
  
====================================================================================================

var romanMatrix = [
  [1000, 'M'],
  [900, 'CM'],
  [500, 'D'],
  [400, 'CD'],
  [100, 'C'],
  [90, 'XC'],
  [50, 'L'],
  [40, 'XL'],
  [10, 'X'],
  [9, 'IX'],
  [5, 'V'],
  [4, 'IV'],
  [1, 'I']
];

function convertToRoman(num) {
  if (num === 0) {
    return '';
  }
  for (var i = 0; i < romanMatrix.length; i++) {
    if (num >= romanMatrix[i][0]) {
      return romanMatrix[i][1] + convertToRoman(num - romanMatrix[i][0]);
    }
  }
}