[Javascript] thousand separator

[Paul Novitski]

Shawn,

[I fear this thread will become tiresome to others on the list, so if 
anyone complains perhaps we should move it to the multi-lingual listserve 
'multiweb' at googlegroups.com.  I do find the subject quite interesting.]

Your latest number-formatting script was definitely an improvement.  I have 
these suggestions:
_______________________________

1) The test for Chinese & Japanese should be /(zh-|ja)/ to cover the codes 
ja, zh-tw, zh-cn, zh-hk, & zh-sg.  MSDN list of language codes:
http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml/reference/language_codes.asp
_______________________________

2) To make the function more flexible, I'd add an optional argument whereby 
the caller can specify the language code:

function addCommas_skm_pdn(someNum, langCode){

	if (langCode)
	{
		var regionTest = langCode
	} else {
		var regionTest = navigator.systemLanguage + '' + navigator.language
	}

That way, the function can be used to display different nation's currency 
formats regardless of the local settings of the user's browser.
_______________________________

3) Supporting the Indian pattern (separating the first group of 3 then 2 
thereafter) is easy if both match & replace RegExps are dynamic during the 
loop, inserting the proper Group value with each iteration.  Pseudocode:

- default Group = 3
- zh/ja Group = 4

while (match)
	- replace one
	- if Hindi, Group = 2
	- modify match & replace RegExps
loop
_______________________________

4) The zh/ja group separator, now that I read the fine print, changes to a 
new character for each group of 10,000; see:
http://www.xencraft.com/resources/multi-currency.html#ja-count

This can be handled easily:

[a]
// create array of Chinese/Japanese separators
var aZhJa = new array(U+4E07, U+5104, U+5146, U+4EAC, U+5793, U+79BE, 
U+7A63, U+6E9D, U+6F97, U+6B63, U+8F09, U+6975);

var iteration = 0;

[b]
while (someNum.match(reMatch))
{
		// change the zh/ja separator each time
		if (regionTest.match(/(zh-|ja)/i))
		{ strThou = aZhJa[iteration];}
[b]
	someNum = someNum.replace(reReplace, '$1' + strThou + '$2');
	iteration++;
}

Notes:

[a] I'm unsure how to represent & manipulate UTF-16 character codes in 
JavaScript; I'll have to read up on that.

[b] The ZH/JA separators need to find their way into the match() & 
replace() regexp's, either by loading them all in from the start or by 
modifying the regexp's after each replacement.
_______________________________

5) To keep the loop code from getting too gnarly, it might be desireable to 
separate the formatting into two processes: positioning the separators and 
determining their value.  For example, one could insert "[#]" each time 
where # = the iteration number, then replace those afterward with logic 
like this:

	var iteration = 0;

	while (someNum.match(reMatch))
	{
		someNum = someNum.replace(reReplace, '$1\[' + iteration + '\]$2');
		iteration++;
	}

before: 1234567890

after:  1[3]234[2]567[1]890
or:     1[4]23[3]45[2]67[1]890 (Hindi)
or:     12[2]3456[1]7890 (Chinese/Japanese)

then: 	replace each [#] with separator
		if zh/ja, different character each time
		else single character per language group

	// if Zh/Ja, replace each separator with a different character
	if (regionTest.match(/zh|ja/i)
	{
		for (var i=0; i < aZhJa.length; i++)
		{
			reReplace = "[\" + i + "\]"
			reReplace = new RegExp(reReplace)
			someNum = someNum.replace(reReplace, aZhJa[i])
		}
	// everyone else uses the same separator throughout
	} else {
		someNum = someNum.replace(/\[\d\]/g, sThou)
	}
_______________________________

Finally, here are some links I've found useful while playing with this:

Language Codes (MSDN)
http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml/reference/language_codes.asp

Language Codes:  ISO 639, Microsoft and Macintosh (UNICODE)
http://www.unicode.org/onlinedat/languages.html

Country Codes:  ISO 3166, Microsoft, and Macintosh (UNICODE)
http://www.unicode.org/onlinedat/countries.html

Currency Internationalization, Multiple Currencies and Foreign Exchange 
(XenCraft.com)
http://www.xencraft.com/resources/multi-currency.html

Detect foreign language support using JavaScript (article)
http://builder.com.com/5100-6371-5069931.html