As other commenters have mentioned, Source Maps are the solution to this problem in general. The main reason we don't yet allow signup to RescueJS is that "create a source map" is currently beyond the state of the art for web frameworks. You can't "just" do it.

Over the weekend we spent a few hours trying to hook source maps into the asset pipeline for Rails based on https://github.com/sstephenson/sprockets/pull/311 and upgrading the 'uglifier' rubygem to work with UglifyJS2. We didn't manage to get it quite working within the time limit, but we'll try and push our work-in-progress upstream to get this ball moving again.

They mention that they use source maps (http://www.html5rocks.com/en/tutorials/developertools/source...) at the bottom of the page.