How to Efficiently Replace Accented Characters in a JavaScript String for Improved Sorting?

Efficiently replace all accented characters in a string?

I¹ am looking to improve the string comparison functions in my JavaScript class.

Currently they use string.replace() to perform a global (g) search and replace all accented characters in a string (p{InCombiningDiacriticalMarks} ) with their base form (canonical decomposition using NFD).

Searching the input string for even a few accented characters results in pretty extensive churn - and when searching larger inputs, performance can become sluggish.

Is there are more efficient way to accomplish this?

[1] Edit - Clarifying general issue.

This operation is being done to convert accented German characters to their unaccented form, so that when sorting strings in the "wrong" order (e.g. umlaut ending up before non-umlaut "a"), they can be sorted properly in accordance with local expectations.

It is therefore not adequate to simply search for the accented characters and replace them with their unaccented equivalent - it is necessary to replace accented forms with their base equivalent.

Non- or incorrect normalization can result in the wrong sort order.

[Edit 2]

For a poor man's implementation of near-collation-correct sorting on the client side I need a JavaScript function that does efficient single character replacement in a string.

Here is what I mean (note that this applies to German text, other languages sort differently):

native sorting gets it wrong: a b c o u z ä ö ü
collation-correct would be:   a ä b c o ö u ü z

Basically, I need all occurrences of "ä" of a given string replaced with "a" (and so on). This way the result of native sorting would be very close to what a user would expect (or what a database would return).

Other languages have facilities to do just that: Python supplies str.translate(), in Perl there is tr/…/…/, XPath has a function translate(), ColdFusion has ReplaceList(). But what about JavaScript?

Here is what I have right now.

// s would be a rather short string (something like 
// 200 characters at max, most of the time much less)
function makeSortString(s) {
  var translate = {
    "ä": "a", "ö": "o", "ü": "u",
    "Ä": "A", "Ö": "O", "Ü": "U"   // probably more to come
  };
  var translate_re = /[öäüÖÄÜ]/g;
  return ( s.replace(translate_re, function(match) { 
    return translate[match]; 
  }) );
}

For starters, I don't like the fact that the regex is rebuilt every time I call the function. I guess a closure can help in this regard, but I don't seem to get the hang of it for some reason.

Can someone think of something more efficient?

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