} else if (customIndexField.type === 'number') {
          if ((customIndexField.options as CustomNumberFieldOptions).sortable !== undefined) optionsBody.sortable = (customIndexField.options as CustomNumberFieldOptions).sortable;
        } else {
          throw new FailureByDesign('PARAM_ERROR', 'Parameter `customIndexFields[].type must be `tag`, `text`, or `number`');
        }