code: function(name) {
        if (name in props) {
  
          // Check property descriptor
          var desc = this.getOwnPropertyDescriptor(name);
          if (props[name].nullable === false) {
            throw name + ' is not allowd null or undefined';
          }
  
          return delete obj[name];
        } else {
          throw name + ' is not defined in this struct';
        }
      }
docs: Delete specified property.
  Check property name if defined in advance.