Angular Js -Directive to allow only numbers, alphanumeric validate

Html- controls

<input type='text' ng-model='a' alpha-numeric/>
<input type='text' ng-model='b' numbers-only/>

Directive 
-----------------

app.directive('alphaNumeric', function () {

    return {

        require: 'ngModel',

        link: function (scope, element, attr, ngModelCtrl) {

            function fromUser(text) {

                var transformedInput = text.replace(/[^0-9a-zA-Z\-\s]/g, '');

                console.log(transformedInput);

                if (transformedInput !== text) {

                    ngModelCtrl.$setViewValue(transformedInput);

                    ngModelCtrl.$render();

                }

                return transformedInput; // or return Number(transformedInput)

            }

            ngModelCtrl.$parsers.push(fromUser);

        }

    };

});

-- ------------------------------------

app.directive('numbersOnly', function () {

    return {

        require: 'ngModel',

        link: function (scope, element, attr, ngModelCtrl) {

            function fromUser(text) {

                if (text) {

                    var transformedInput = text.replace(/[^0-9]/g, '');

                    if (transformedInput !== text) {

                        ngModelCtrl.$setViewValue(transformedInput);

                        ngModelCtrl.$render();

                    }

                    return transformedInput;

                }

                return undefined;

            }

            ngModelCtrl.$parsers.push(fromUser);

        }

    };

});