Route resolver for Rails3 into Backbone-style routes

router.js

// Router.js 0.1.0
// (c) 2011 Doc Ritezel
// Freely distributable under the MIT license.
//
// Load this before rails_routes.js (generated by routes_to_javascript.rb)
// Enables:
//   var c = new Backbone.Controller({ routes: { Routes.root(): 'index' } });
//   $('a.delete').attr('href', Routes.delete_item(3));

(function(){
  var root = this;
  var getParams = /(:([\w\d]+)|\*([\w\d]+))/g;
  function Routes() {
    this.routes = {};
  }
  root.Routes = new Routes();
  root.Routes.url_for = function urlFor(name) {
    return this.routes[name];
  };
  function router(pathMatch) {
    var parts = pathMatch.match(getParams);
    return function pathRouter() {
      var i, l, p, sliced, args, path = pathMatch.toString();
      if (arguments.length) {
        if (typeof arguments[0] === 'object') {
          args = arguments[0];
          for (i = 0, l = parts.length, p = parts[i]; i < l; i++) {
            sliced = p.slice(1);
            if (args[sliced] !== undefined) {
              path = path.replace(p, args[sliced]);
            }
          }
        } else {
          args = Array.prototype.slice.call(arguments);
          for (i = 0, l = parts.length, p = parts[i]; i < l; i++) {
            if (args[i] !== undefined) {
              path = path.replace(p, args[i]);
            }
          }
        }
      }
      return path;
    };
  }
  root.Routes.add_routes = function addRoutes(routes) {
    var name;
    for (name in routes) {
      this.routes[name] = routes[name];
      this[name + "_path"] = router(routes[name]);
    }
  };
})();

routes_to_javascript.rb

# drop into config/initializers

Rails.application.reload_routes!
routes_path = File.expand_path('public/javascripts/rails_routes.js', Rails.root)
all_routes = Rails.application.routes.routes.reject { |r| r.name.to_s == '' }

routes = all_routes.inject({}) do |memo, route|
  memo[route.name] = route.path.sub('(.:format)', '')
  memo
end

routes_template = <<ROUTES_TEMPLATE
(function() {
  var routes = RAILS_ROUTES;
  window.Routes.add_routes(routes);
})();
ROUTES_TEMPLATE

File.open(routes_path, 'w') {|f| f.write routes_template.sub('RAILS_ROUTES', routes.to_json) }