Helps you identify unused functions in your javascript.

js_reek.rb

js_files = Dir['*.js', 'lib/*.js', 'messages/*.js']

defined_functions = js_files.map {|file|
  [ file, File.read(file).scan( /function ([_a-z0-9]+)/i ).flatten.uniq ]
}.reject {|file_name, functions| functions.empty? }

called_functions = js_files.map {|file|
  defined_functions.map {|file_name, functions| functions }.flatten.map do |function|
    File.read(file).scan /(?<!function )#{function}/
  end
}.flatten.uniq

defined_functions.each do |file_name, functions|
  unused_functions = functions.reject {|function| called_functions.include? function }
  if unused_functions.any?
    puts "\n#{file_name} contains #{unused_functions.count} unused functions:\n"
    puts unused_functions.join(', ')
  end
end