Question

How do I write a regex in javascript that matches all twitter like mentions (@something), but not email addresses.

I need to capture an unlimited number of mentions in a huge text field. Strings that have a non-printable characters and parentheses preceding the “@”, should be captured.

Answer 1

/(?<!\w)@\w+/g

would be a simple solution, but since JavaScript does not support lookbehind it becomes a non-trivial task:

var matches = str.match(/(^|\W)@\w+/g);
for (var i=0; i<matches.length; i++)
    matches[i] = matches[i].replace(/^[^@]/, "");

If you want to support a wider range of characters (as from your edit), you would use

/(?<![^\s(]@\S+/g // or respectively
/(^|[\s(])@\S+/