Angular validate only when input has data - angularjs

Question

I am using angular 1.4 with ng-pattern and a custom async validator.
I have 2 fields with validation, one is required and the other is not. I need to validate the second filed WHEN it DOES have something in it. Issue is that I cannot submit the form when the second field's validators do not pass.
Is there an elegant way of doing this?
Thanks
<input
name="name"
type="text"
ng-model="model.software.name"
required>
<div ng-messages="myForm.myInput.$error" ng-if="myForm.name.$touched && myForm.name.$invalid">
<p ng-message="required">Required warning</p>
</div>
<input
name="myInput"
type="text"
ng-model="myInput"
ng-pattern="/someregex/"
async-validator>
<div ng-if="myForm.myInput.$pending">PENDING</div>
<div ng-messages="myForm.myInput.$error" ng-if="myForm.myInput.$touched && myForm.myInput.$invalid">
<p ng-message="pattern">Pattern warning</p>
<p ng-message="asyncValidator">async warning</p>
</div>
<button ng-click="process()" ng-disabled="myForm.$invalid">Process</button>
And here is my validator:
app.directive('asyncValidator', ['$http', '$q', function ($http, $q) {
return {
require : 'ngModel',
link : function (scope, element, attrs, ngModel) {
ngModel.$asyncValidators.asyncValidator = function (modelValue, viewValue) {
return $http.post('path', {value : viewValue}).then(
function (response) {
if (not_good) {
return $q.reject(not_good);
}
return true;
}
);
};
}
};
}]);

Answer 1

After a bit more digging I found that it was my asyncvalidator that was not allowing blank values. This works, but if there is better way please let me know.
Thanks Anid and to everyone.
The adjusted validator:
app.directive('asyncValidator', ['$http', '$q', function ($http, $q) {
return {
require : 'ngModel',
link : function (scope, element, attrs, ngModel) {
ngModel.$asyncValidators.asyncValidator = function (modelValue, viewValue) {
if (ngModel.$isEmpty(viewValue)) {
return $q.resolve();
}
return $http.post('path', {value : viewValue}).then(
function (response) {
if (not_good) {
return $q.reject(not_good);
}
return true;
}
);
};
}
};
}]);