setValidity

setValidity.js

    module.directive('setValidity', ['$parse',
        function($parse) {
            // no need for form. better
            return {
                require: "ngModel",
                scope: {
                    'setValidity': '=setValidity',
                    'ngDisabled': '=ngDisabled'
                },
                controller: function($scope, $element, $attrs, $transclude) {
                    $scope.isEmpty = function(elements) {
                        var type = typeof(elements);
                        var sum = 0;
                        // what
                        switch (type) {
                            case 'object':
                                angular.forEach(elements, function(value, key) {
                                    sum += value.length;
                                });
                                break;
                            case 'number':
                                sum = elements;
                                break;
                            default:
                                // It will never work but eyh (in case undefined)
                                sum = elements || 0;
                                break;
                        }
                        return sum === 0;
                    };
                },
                link: function(scope, ele, attrs, c) {

                    var getValidity = function() {
                        var disable = scope.ngDisabled;
                        var empty = scope.isEmpty(scope.setValidity);
                        return (disable || !empty);
                    };

                    c.$setValidity('custom', getValidity());
                    scope.$watch('setValidity', function(newv) {
                        c.$setValidity('custom', getValidity());
                    }, true);
                    scope.$watch('ngDisabled', function() {
                        c.$setValidity('custom', getValidity());
                    });
                }
            };
        }
    ]);