Converts roman numerals to arabic numerals and arabic numerals to roman numerals. Replaces roman numerals with arabic numerals.

roman.numerals.js

/**
* Converts roman numerals to arabic numerals and arabic numerals to roman numerals.
* @author Daniel Wachsstock
* @internal Modified by khornberg
* @license MIT
* @link from http://bililite.com/blog/2009/03/09/roman-numerals-in-javascript/ Daniel's orginal post
*
*/
var romanNumerals = [
    [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']
];


/**
* Converts arabic numeral to roman numeral
* @method arabic2roman
* @param {integer} arabic numeral
* @return {string} roman numeral
*/
arabic2roman = function(n){
	var r = '';
	for (var i = 0; i < romanNumerals.length; ++i){
		for (var x = romanNumerals[i]; n >= x[0]; n -= x[0]) r += x[1];
	}
	return r;
}

/**
* Converts roman numeral to arabic numeral
* @method roman2arabic
* @param {string} roman numeral
* @return {integer} arabic numeral
*/
roman2arabic = function(r){
	// Test if string is a valid roman numeral
	var rom = '^((CM|CD)|(D)?(C){0,3})((XC|XL)|(L)?(X){0,3})((IX|IV)|(V)?(I){0,3})$';
	var romanRegExp = new RegExp(rom ,'mi');
	if(romanRegExp.test(r)) {
		var n = 0;
		for (var i = 0; i < romanNumerals.length; ++i){
			for (var x = romanNumerals[i], l = x[1].length; r.substr(0,l).toUpperCase() == x[1]; r = r.substr(l).toUpperCase()) 
	            n += x[0];
		}
		return n;
	}
	else {
		return r;
	}
}

/**
* Replaces roman numerals with arabic numerals
* @method replaceRoman
* @param {string} String with roman numerals
* @return {string} String with roman numerals replaced with arabic numerals
*/
replaceRoman = function(str) {
	// get roman numerals from string
	var matches = str.match(/((CM|CD)|(D)?(C){0,3})((XC|XL)|(L)?(X){0,3})((IX|IV)|(V)?(I){0,3})(?=(\s|[\.,;:-])|$)/gi);

	// remove "", null, undefined, and 0
	matches = matches.filter(function(e){return e});

	// replace the roman numerals with arabic numerals
	for (var i = matches.length - 1; i >= 0; i--) {
		var arabicNumeral = roman2arabic(matches[i]);
		var romanNumeral = new RegExp('\\b' + matches[i] + '(?=(\\s|[\.,;:-])|$)', 'gi');
		var str = str.replace(romanNumeral, arabicNumeral);
	}

	return str;
}
 
// Tests
var testRoman = ['MCMXC', 'MDCLXIV', 'MMVIII', 'cxii', 'xcv', 'iix', 'xi', 'iii', 'iota', 'I\'m', 'Verily'];
var testArab = [2, 150, 2014, 48, 87];
var testReplace = [
'Chapter. verse	before John i. 10 after',
'Chapter before 1Pe i. after',
'Chapter II Cor. v:18–20',
'Chapter.verse–verse before Jude vi; i John xii; iii JOhn xiii-xiv after',
'Chapter.verse–verse before John xii-xiii after',
'Chapter:verse;chapter:verse before John i:10-11, xii:12-24; v:20 after',
'Chapter before Gen i after',
'Chapter.verse–verse Mar 15; Jul 10, 2010; Jan 15, 1989',
'Chapter:verse;chapter:verse before John i:10, 12; v:20 after',
'Chapter before John i after',
'Chapter. before John i. after',
'Chapter, before John i, after',
'Chapter:verse	before John i:10 after',
'Chapter:verse-verse before John i:10-12 after',
'Chapter:verse,verse before John i:10, 20 after',
'Chapter:verse-verse before Johni1:10-12 after',
'Chapter:verse–verse before John i:10–20 after',
'Chapter.verse–verse before John i.10–20 after',
'Chapter. verse	before Psalm i. 1 after',
'Chapter. verse	before Psalm ii. 1 after',
'Chapter. verse	before Psalm iii. 1 after',
'Chapter. verse	before Psalm iv. 1 after',
'Chapter. verse	before Psalm v. 1 after',
'Chapter. verse	before Psalm xlvi. 1 after',
'Chapter. verse	before Psalm lvii. 1 after',
'Chapter. verse	before Psalm viii. 1 after',
'Chapter. verse	before Psalm xcix. 1 after',
'Chapter. verse	before Psalm x. 1 after',
'Chapter. verse	before Psalm cxi. 1 after',
];

var testReplaceCorrectResults = [
'Chapter. verse	before John 1. 10 after',
'Chapter before 1Pe 1. after',
'Chapter 2 Cor. 5:18–20',
'Chapter.verse–verse before Jude 6; 1 John 12; 3 JOhn 13-14 after',
'Chapter.verse–verse before John 12-13 after',
'Chapter:verse;chapter:verse before John 1:10-11, 12:12-24; 5:20 after',
'Chapter before Gen 1 after',
'Chapter.verse–verse	Mar 15; Jul 10, 2010; Jan 15, 1989',
'Chapter:verse;chapter:verse before John 1:10, 12; 5:20 after',
'Chapter before John 1 after',
'Chapter. before John 1. after',
'Chapter, before John 1, after',
'Chapter:verse	before John 1:10 after',
'Chapter:verse-verse before John 1:10-12 after',
'Chapter:verse,verse before John 1:10, 20 after',
'Chapter:verse-verse before Johni1:10-12 after',
'Chapter:verse–verse before John 1:10–20 after',
'Chapter.verse–verse before John 1.10–20 after',
'Chapter. verse	before Psalm 1. 1 after',
'Chapter. verse	before Psalm 2. 1 after',
'Chapter. verse	before Psalm 3. 1 after',
'Chapter. verse	before Psalm 4. 1 after',
'Chapter. verse	before Psalm 5. 1 after',
'Chapter. verse	before Psalm 46. 1 after',
'Chapter. verse	before Psalm 57. 1 after',
'Chapter. verse	before Psalm 8. 1 after',
'Chapter. verse	before Psalm 99. 1 after',
'Chapter. verse	before Psalm 10. 1 after',
'Chapter. verse	before Psalm 111. 1 after',
];

var i = 0;
for (; i<testRoman.length; i++) {
  console.log(testRoman[i] + ": " + roman2arabic(testRoman[i] );
}
for (; i<testArab.length; i++) {
  console.log(testArab[i] + ": " + arabic2roman(testArab[i]));
}
var match = false;

for (; i<testReplace.length; i++) {
	console.log("Test: " + testReplace[i] + "\nResu: " + replaceRoman(testReplace[i]) + "\nShou: " + testReplaceCorrectResults[i]);
	match = (replaceRoman(testReplace[i]) == testReplaceCorrectResults[i]) ? true : false;
	console.log(match);
}

//sdg