Sprockets 2.8.1 Precompile CoffeeScript for non rack apps

rakefile.rb

namespace :js do
  require 'sprockets'

  environment = Sprockets::Environment.new(File.dirname(__FILE__))
  environment.append_path 'src/bower'
  environment.append_path 'src/coffee'
  source_code = environment['app.coffee']

  desc 'compile CoffeeScript with Sprockets'
  task :compile do
    bundle_file = './build/js/app.bundle.js'
    File.open(bundle_file, 'w'){ |f| f.write(source_code) }
    puts "app.coffee -> #{bundle_file}"
  end

  desc 'compile and minify CoffeeScript with Sprockets'
  task :min do
    require 'uglifier'
    bundle_min = './dist/js/app.bundle.min.js'
    source_min = Uglifier.compile(source_code)
    File.open(bundle_min, 'w'){ |f| f.write(source_min) }
    puts "app.coffee -> #{bundle_min}"
  end
end