how we can get which validation is invalid in AngularJS -

i have code figure out if element valid or invalid in directive :

mymodule.directive('mydirective',function(){ return {     restrict: 'a',     scope: {},     require:'ngmodel',     link: function(scope,element,attrs,ctrl){          if(ctrl.$invalid){             //do         }     } }}); 

so problem how can determine type of validation invalid, required? max-length? other custom-validations?

because need generate proper validation-message show.

ngmodelcontroller (or ctrl, in example) has $error property can use see validation errors are.

so if "required" validation has failed, property truthy: ctrl.$error.required