//1. in ui-router:
controller: 'ctrl',
resolve: {
  friends: ['$http', function($http) {
    return $http.get('/api/friends.json').then(function(data) {
      return response.data;
    });
  }]
}

//2. in controller:
.controller('ctrl', ['$scope', 'friends', function($scope, friends) {
  $scope.friends = friend;
}]);

//3. or using wrapping Friends factory instead of $http:
controller: 'ctrl',
resolve: {
  friends: ['Friends', function(Friends) {
    return Friends.get();
  }]
}

//4. keys: when using $http + resolve, using then() instead of success() in factory:
.factory('Friends', function($http) {
 return {
  get: function($http) {
    return $http.get('api/friends.json').then(function(response) {
      return response.data;
    });
  }
 }
}
//5. using resolve object in router can resolve dependencies
BEFORE controller instantiates.