Reduce your slug size on Heroku!

You don't need app/javascript and node_modules after compiling assets. Enhance the assets:precompile task and delete them so they don't get added to your Heroku slug! Small slugs allow for fast boot up times and better scaling. This also helps stay below the 500MB size limit!

Rake::Task["assets:precompile"].enhance do
  next unless Rails.env.production?

  ["#{Dir.pwd}/app/javascript", "#{Dir.pwd}/node_modules"].each do |dir_path|