在Controller中访问$ rootScope方法

Question

In this ng-book JSBin , does $scope.$watch() resolves to $rootScope.$watch() due to prototypal inheritance.

Can we inject $rootScope explicitly inside the controller so that $scope would be same as $rootScope inside the controller, without going through prototypal inheritance?

Replicating code here for reference:

    // open this example and type person.name into the test field
    angular.module('myApp', [])
    .controller('MyController',
    ['$scope', '$parse', function($scope, $parse) {

      $scope.person = {
        name: "Ari Lerner"
      };

      $scope.$watch('expr', function(newVal, oldVal, scope) {
        if (newVal !== oldVal) {
          // Let's set up our parseFun with the expression
          var parseFun = $parse(newVal);
          // Get the value of the parsed expression, set it on the scope for output
          scope.parsedExpr = parseFun(scope);
        }
      });
    }]);

Answer 1

Just inject it the same way as $scope or $parse , anything defined on $rootScope will be then accessible inside your controller.

app.controller('MyController', ['$scope', '$parse', '$rootScope', 
   function($scope, $parse, $rootScope) {

      $rootScope.foo();

      console.log($rootScope.bar);
   }
]);

etc.

Answer 2

If you intend to use the rootScope so badly, it has a provider just as scope does. Including '$rootScope' into your controller as you do with the '$scope' does the trick.

There's also the $parent attribute of the $scope which could come in handy, but IMO it tends to make code less maintainable if abused. In particular when multiple scopes are nested, as you need to traverse the whole hierarchy.