Angular: <select ng-required = "options.length"> with filter

I have:

<select name="club" id="club" ng-model="currentUser.club_id" ng-options="club.id as club.name for club in clubs | filter:{ country_id: currentUser.country_id }" required></select>

      

        
        
        
      

    

I'm happy that, since I'm a filter

list clubs

, there are times when it <select>

doesn't <option>

, which means the attribute required

makes the form unsubmittable.

I could do

<select ng-required="(clubs | filter:{ country_id: currentUser.country_id }).length"></select>

      

        
        
        
      

    

but maybe there is a more elegant way to do it. Something like:

<select ng-required="$element.options.length"></select>

      

        
        
        
      

    

Is my intuition correct? How can I do this?