code: function validateObjectRequired(options, modelObject, entity, parents, errors) {
    for (var key in modelObject) {
      if (!modelObject[key].type && entity) {
        validateObjectRequired(
          options,
          modelObject[key],
          entity[key],
          parents + '.' + key,
          errors);
      } else if (!options.notRequired && modelObject[key].required && (!entity || !entity[key])) {
        if (!errors.notFound) errors.notFound = [];
        var fieldName = parents + '.' + key;
        errors.notFound.push(fieldName);
        errors.text.push('Field ' + fieldName + ' not found');
      }
    }
  
    return errors;
  }
docs: check for required fields recursively