validex directive for Angular.js

app.directive('validex', function(){
   return {
     require: 'ngModel',
     link: function(scope, element, attrs, modelCtrl) {
       modelCtrl.$parsers.push(function (val) {
         if (!attrs.validex) return false;
         var pattern = attrs.validex;
         var flags = attrs.vflags ? attrs.vflags : '';
         var exp = new RegExp(pattern,flags);
         
         switch (pattern) {
             
           case 'email': 
             exp = /[A-Z0-9._%+-]+@[A-Z0-9-]+.+.[A-Z]{2,4}/igm;
           break;
             
           case 'url': 
             exp = /https?:\/\/(?:[-\w]+\.)?([-\w]+)\.\w+(?:\.\w+)?\/?.*/i;
           break;
             
           case 'phone': 
             exp = /^\+?[2-9]\d{2}[0-9]\d{3}\d{4}$/;
           break;
             
           case 'tw-username':
             exp = /^@([A-Za-z0-9_]{3,15})$/;
           break;
             
           case 'card':
              exp = /^(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|6(?:011|5[0-9][0-9])[0-9]{12}|3[47][0-9]{13}|3(?:0[0-5]|[68][0-9])[0-9]{11}|(?:2131|1800|35\d{3})\d{11})$/;
           break;
             
           case 'hex':
             exp = /\#([a-fA-F]|[0-9]){3, 6}/;
           break;
             
           default:
             exp = new RegExp(pattern,flags);
           break;
             
         }
         
         if (val.match(exp))
         {
           element.removeClass('error');
           scope.status = 'ok';
         }
         else {
           element.addClass('error');
           scope.status = 'error!';
         }
         
       });
     }
   };
});

// Use Twitter username (Example: @username): <input validex validex="^@([A-Za-z0-9_]{3,15})$" type="text">