rails: dynamically pickup controller-named-assets for pre-compilation

assets.rb

# config/initializers/assets.rb
javascripts = [...]
stylesheets = [...]
images      = [...]
fonts       = [...]

# NOTE: dynamically include for precompile: controller specific .coffee, .js and .scss, .css
#
# step 1: collect controller basenames
controllers = Dir.glob(File.join(Rails.root, 'app', 'controllers', '*.rb'))
                 .collect { |e| File.basename(e, '.rb').split('_').first }
controllers -= ['application'] # exclude the main file
#
# step 2: collect /app/assets/javascripts/*.coffee,js (that match controller names)
javascripts += Dir.glob(File.join(Rails.root, 'app', 'assets', 'javascripts', "{#{controllers.join(',')}}.{coffee,js}"))
                  .collect { |e| File.basename(e) }
#
# step 3: collect /app/assets/stylesheets/*.scss,css (that match controller names)
stylesheets += Dir.glob(File.join(Rails.root, 'app', 'assets', 'stylesheets', "{#{controllers.join(',')}}.{scss,css}"))
                  .collect { |e| File.basename(e) }

Rails.application.config.assets.precompile += (javascripts + stylesheets + images + fonts)