Refactor @jonhyman's fix a bit

Author: carsomyr

lib/tasks/requirejs-rails_tasks.rake

@@ -32,6 +32,7 @@ namespace :requirejs do
   end
 
   requirejs = ActiveSupport::OrderedOptions.new
+  path_extension_pattern = Regexp.new("\\.(\\w+)\\z")
 
   task clean: ["requirejs:setup"] do
     FileUtils.remove_entry_secure(requirejs.config.source_dir, true)
@@ -161,9 +162,10 @@ OS X Homebrew users can use 'brew install node'.
 
         built_asset_path = requirejs.config.build_dir.join(asset_name)
 
+        # Compute the digest based on the contents of the compiled file, *not* on the contents of the RequireJS module.
         file_digest = ::Rails.application.assets.file_digest(built_asset_path)
         hex_digest = Sprockets::DigestUtils.pack_hexdigest(file_digest)
-        digest_name = asset.logical_path.sub(/\.(\w+)$/) { |ext| "-#{hex_digest}#{ext}" }
+        digest_name = asset.logical_path.gsub(path_extension_pattern) { |ext| "-#{hex_digest}#{ext}" }
 
         digest_asset_path = requirejs.config.target_dir + digest_name