gistfile1.txt

function checkSlugAvailability(slug) {
    if (slug) {
        $scope.$apply(function() {
                $q.when((new ProfileSlugModel({
                    id: slug
                })).exists(), function(result) {
                    if (result) {
                        isSlugAvailable = false;
                    } else {
                        isSlugAvailable = true;
                    }
                }, function() {
                    isSlugAvailable = null;
                });
            };
        }
    }
}

function isSlugAvailable() {
    //whatevs
}

this.isSlugAvailable = isSlugAvailable;
this.checkSlugAvailability = checkSlugAvailability;