How to use the @nestjsx/util.isDateString function in @nestjsx/util

const parsed = JSON.parse(val);

      if (!isDate(parsed) && isObject(parsed)) {
        // throw new Error('Don\'t support object now');
        return val;
      } else if (
        typeof parsed === 'number' &&
        parsed.toLocaleString('fullwide', { useGrouping: false }) !== val
      ) {
        // JS cannot handle big numbers. Leave it as a string to prevent data loss
        return val;
      }

      return parsed;
    } catch (ignored) {
      if (isDateString(val)) {
        return new Date(val);
      }

      return val;
    }
  }