Breaking the readability is the trade-off you have to make, though I think it's worth it for production code, it really brings the file sizes down and if you concatenate all your javascripts in to a single file you can really cut down on requests too.

If you use Google chrome you can click the '{}' icon inside the developer tools to 'pretty print' the javascript which helps a little!

There's also JavaScript Source Maps which you might want to look in to: http://www.html5rocks.com/en/tutorials/developertools/source...