服务层

业务逻辑以 TReturn<T> 格式返回：

type TReturn<T> = [Error | null, T | undefined];

export async function getUserInfo(id: number): TReturn<UserInfo> {
  try {
    const user = await knex("user").where({ id }).first();
    return [null, user];
  } catch (err) {
    return [err as Error, undefined];
  }
}