mongodb查询结果返回object的解构

Question

假设我们开始一个mongodb查询语句，如下所示：

const user = await db.users.findOne(...);
console.log(user);

结果是好的。

{
  _id: 5f60647c28b90939d0e5fb24,
  tenantId: '5e6f7c86e7158b42bf500371',
  username: 'aaaa',
  email: 'xxxx@yy.com',
  createdAt: 2020-09-15T06:51:40.531Z,
  updatedAt: 2020-09-15T06:51:40.531Z,
  __v: 0
}

然后我们使用解构。

const { _id, username, ...others } = user;
console.log(others);

我们得到了一个奇怪的东西：

[
  [
    '$__',
    InternalCache {
      strictMode: false,
      selected: [Object],
      shardval: undefined,
      saveError: undefined,
      validationError: undefined,
      adhocPaths: undefined,
      removing: undefined,
      inserting: undefined,
      saving: undefined,
      version: undefined,
      getters: {},
      _id: 5f60647c28b90939d0e5fb24,
      populate: undefined,
      populated: undefined,
      wasPopulated: false,
      scope: undefined,
      activePaths: [StateMachine],
      pathsToScopes: {},
      cachedRequired: {},
      session: undefined,
      '$setCalled': Set(0) {},
      ownerDocument: undefined,
      fullPath: undefined,
      emitter: [EventEmitter],
      '$options': [Object]
    }
  ],
  [ 'isNew', false ],
  [ 'errors', undefined ],
  [ '$locals', {} ],
  [ '$op', null ],
  [
    '_doc',
    {
      _id: 5f60647c28b90939d0e5fb24,
      tenantId: '5e6f7c86e7158b42bf500371',
      username: 'aaaa',
      email: 'xxxx@yyy.com',
      createdAt: 2020-09-15T06:51:40.531Z,
      updatedAt: 2020-09-15T06:51:40.531Z,
      __v: 0
    }
  ],
  [ '$init', true ]
]

这里发生了什么事？如何让解构再次发挥作用呢？Object.entries(others)上出现相同的错误。有一个解决办法，我可以把它串起来，然后再解析回来。但这显然是多余的。

Answer 1

默认情况下，Mongoose查询返回Mongoose Document class的一个实例。这就是为什么你在解构之后会得到奇怪的结果。在您的例子中，您应该在查询中使用.lean()来获得预期的结果；

Answer 2

当我使用mongoose时，这对我是有效的：

const user = UserModel.findOne({...});
const { _id, username, ...others } = user.toObject();