最佳答案
Efficiently replace all accented characters in a string?
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?
Answers below fall in two categories:
- String replacement functions of varying degrees of completeness and efficiency (what I was originally asking about)
- A late mention of
String#localeCompare, which is now widely supported among JS engines (not so much at the time of the question) and could solve this category of problem much more elegantly.
