code: function(items, propertyName) {
          if(!items) return false;
  
          var hasProperty = true;
          for(var i = 0; i < items.length; i++) {
              if(isNaN(items[i][propertyName]))
                  hasProperty = false;
          }
          return hasProperty;
      }
docs: Method checking if all items of an array have a specific number property