How to add custom validation to an AngularJS form?

Question

I have a form with input fields and validation setup by adding the required attributes and such. But for some fields I need to do some extra validation. How wou

Answer 1

Here's a cool way to do custom wildcard expression validations in a form (from: Advanced form validation with AngularJS and filters):

app.directive('ensureExpression', ['$http', '$parse', function($http, $parse) {
    return {
        require: 'ngModel',
        link: function(scope, ele, attrs, ngModelController) {
            scope.$watch(attrs.ngModel, function(value) {
                var booleanResult = $parse(attrs.ensureExpression)(scope);
                ngModelController.$setValidity('expression', booleanResult);
            });
        }
    };
}]);

jsFiddle demo (supports expression naming and multiple expressions)

It's similar to ui-validate, but you don't need a scope specific validation function (this works generically) and ofcourse you don't need ui.utils this way.