Client side URL helpers generated from Rails routes

client_routes.js.erb

<%= ClientRoutes.to_js %>

client_routes.rb

class ClientRoutes
  attr_reader :routes
  def initialize
    @routes = []

    Rails.application.routes.routes.each do |route|
      @routes.push ActionDispatch::Routing::RouteWrapper.new(route)
    end

    @routes
  end

  def self.to_js(options={})
    as = options[:as] || :path

    final_js = ""
    routes = ClientRoutes.new.routes

    routes.reject! { |r| r.internal? || r.engine? || r.name.empty? }

    # Voodoo starts here
    routes.each do |route|
      arguments = []
      return_statement = "return "
      route.path.gsub(/\(.:format\)/, '').split('/').each do |url_part|
        next if url_part.empty?
        if url_part[0] == ':'
          argument = url_part.tr(':', '')
          arguments << argument
          return_statement << "\"/\" + #{argument}"
        else
          return_statement << "\"/#{url_part}\""
        end
        return_statement << " + "
      end
      return_statement << "\"\";"

      template_renderer = ERB.new("var <%= route.name %>_<%= as %> = function (<%= arguments.join(', ') %>) {<%= return_statement %>};")
      final_js << template_renderer.result(binding)
    end
    final_js
  end
end