Angular navigation menu controller from Begin to Code

navMenuCtrl.js

// see the very bottom of http://angular-rails.com/find_and_browse.html
// by omitting second parameter, we tell angular we're looking for existing module.
var controllers = angular.module('basicControllers');

controllers.controller('NavMenuCtrl', ['$scope', '$stateParams', '$state', 'ProgramCache',
  function($scope, $stateParams, $state, ProgramCache) {
    // variables
    $scope.menuStates = []; // all of the menu items, each a complete state
    // IMPORTANT: we are binding global program service to local program scope!
    // this lets us update menu item content on the fly, since our template will be digested.
    $scope.userId = 0;

    // functions
    // format an href so that target state gets a bunch of state params
    $scope.menuStateHref = function(targetState) {
      return $state.href(targetState, {
        program_id: $scope.program.id,
        user_id: $scope.userId
      });
    }
    // new state has been navigated to, so we need to refresh menu item list
    $scope.$on('$stateChangeSuccess', function() {
      $scope.updateMenuItems();
    });

    // changes $scope.menuStates to be correct set of menu items for this state view.
    // list to use comes from the data section of state definition in routes
    $scope.updateMenuItems = function() {
      var allStates = $state.get(); // get list of all states
      $scope.menuStates = []; // clear list
      if ($state.current.data !== null && $state.current.data !== undefined) {
        if ($state.current.data.hasOwnProperty("menu")) {
          // here's where we stop being careful and assume the menu data is formatted correctly
          $scope.menuStates = _.map($state.current.data.menu.states, function(stateName) {
            return _.findWhere(allStates, {
              name: stateName
            });
          });
        }
      }
    }
    // since we shouldn't show an empty menu
    $scope.isEmpty = function() {
      var emptiness = ($scope.menuStates === null || $scope.menuStates === undefined || $scope.menuStates.length < 1);
      log.debug("isEmpty? " + (emptiness ? "true" : "false"));
      return emptiness;
    };

    // init
    $scope.updateMenuItems();
  }
]);