Custom Elements development server

server.rb

# Start server:
# 
#     $ shotgun -s Puma -o 127.0.0.1 -p 9393 server.rb
# 
# You can load ES 6 file like this:
# 
#     <style>
#       <%=js '/src/my-custom-element.js' %>
#     </style>
require 'sinatra'
require 'pathname'
require 'erb'
require 'babel/transpiler'

configure do
  set :app_file, (ENV['APP_FILE'] || File.expand_path('.'))
end

helpers do
  def js(path)
    full_path = File.join(settings.app_file, path)
    Babel::Transpiler.transform(File.read(full_path))['code']
  end

  def example(code)
    <<EOH
<pre><code>
#{escape_html code}</code></pre>
#{code}
EOH
  end
end

get '/*' do
  path = File.join(settings.app_file, clean_path_info(unescape(request.path_info)))
  path = Pathname(path)
  if path.file?
    content_type mime_type(path.extname)
    erb path.read
  elsif path.directory?
    index = path + 'index.html'
    if index.file?
      erb index.read
    else
      404
    end
  else
    404
  end
end

not_found do
  'Not Found'
end