JavaScript + Unicode regexes

Question

How can I use Unicode-aware regular expressions in JavaScript?

For example, there should be something akin to \\w that can match any code-point in Lette

Answer 1

Having also not found a good solution, I wrote a small script a long time ago, by downloading data from the unicode specification (v.5.0.0) and generating intervals for each unicode category and subcategory in the BMP (lately replaced by a small Java program that uses its own native Unicode support).

Basically it converts \p{...} to a range of values, much like the output of the tool mentioned by Tomalak, but the intervals can end up quite large (since it's not dealing with blocks, but with characters scattered through many different places).

For instance, a Regex written like this:

var regex = unicode_hack(/\p{L}(\p{L}|\p{Nd})*/g);

Will be converted to something like this:

/[\u0041-\u005a\u0061-\u007a...]([...]|[\u0030-\u0039\u0660-\u0669...])*/g

Haven't used it a lot in practice, but it seems to work fine from my tests, so I'm posting here in case someone find it useful. Despite the length of the resulting regexes (the example above has 3591 characters when expanded), the performance seems to be acceptable (see the tests at jsFiddle; thanks to @modiX and @Lwangaman for the improvements).

Here's the source (raw, 27.5KB; minified, 24.9KB, not much better...). It might be made smaller by unescaping the unicode characters, but OTOH will run the risk of encoding issues, so I'm leaving as it is. Hopefully with ES6 this kind of thing won't be necessary anymore.

Update: this looks like the same strategy adopted in the XRegExp Unicode plug-in mentioned by Tim Down, except that in this case regular JavaScript regexes are being used.