Sprockets Es6Coffee
If we are using Coffeescript with ES6 modules, we do not want our Coffeescript compiled output to be wrapped in IIFEs as this is not supported by the ES6 spec.
Usage
Spec the gem in your Gemfile and bundle install.
gem 'sprockets-es6-coffee'
The gem overrides the .coffee extension to not wrap Coffeescript compiled output in an IIFE if it will be processed by the .es6 module preprocessor.