Damn simple JavaScripts bundler for Sinatra

gistfile1.rb

# Adjust the line that says Dir.chdir so it points to the path where your 
# JavaScripts are stored.
#
# Usage:
# Instead of linking scripts one by one with <script> tags, as in:
# <script src="/js/jquery-1.5.2.min.js"></script>
# <script src="/js/underscore.js"></script>
# <script src="/js/backbone-min.js"></script>
#
# You can now go:
#
# <script src="/scripts.js?these=jquery,underscore,backbone"></script>
#
# Probably wise to add long expiry headers in production.

get '/scripts.js' do
  content_type 'application/javascript'
  these, scripts = params[:these].split(',').map { |s| s + '*' }.join(','), []
  Dir.chdir Sinatra::Application.root + '/public/js'
  Dir["{#{these}}.js"].each do |script|
    scripts << File.read(script)
  end
  scripts.join(";")
end