class Middleman::Rack::MinifyJavascript

def call(env)
  status, headers, response = @app.call(env)
  if env["PATH_INFO"].match(/\.js$/)
    compressor = ::Uglifier.new

    if response.is_a?(::Rack::File) or response.is_a?(Sinatra::Helpers::StaticFile)
      uncompressed_source = File.read(response.path)
    else
      uncompressed_source = response.join
    end
    minified = compressor.compile(uncompressed_source)
    headers["Content-Length"] = ::Rack::Utils.bytesize(minified).to_s
    response = [minified]
  end
  [status, headers, response]
end