We use Atom's syntax highlighter for syntax highlighting on npmjs.com -- I originally wrote onigurumajs, because I was seeing if we could viably remove the website's only compiled dependency (oniguruma) ... I wrote it over vacation, and then had to put the work down.
I would love help to see the library over the finish line; on a grammar by grammar basis it would be great to figure out what the JavaScript regex engine is missing, and try to shim the logic.
why???
The great thing about using oniguruma, is that it lets you leverage the huge collection of grammars available for TextMate -- unfortunately JavaScript's regex engine doesn't support quite a few rules that are present in TextMate grammars.