CoffeeScript Source Maps
One of the primary reasons developers give as staying away from CoffeeScript in the browser – the need to debug generated code – is no long a valid reason.
Support for Source Maps has been added to the new “better CoffeeScript Compiler” CoffeeScriptRedux and is available in Google Chrome and allows you to see the original CoffeeScript source your executed JavaScript code came from. You can’t yet type CoffeeScript into the console or step debugger, but, it’s a great step up from debugging previously.
Read more at Ryanflorence.com