Mongodb Mongoose 查询以获取内部数组和该内部数组中的特定元素

我正在try 使用Mongoose的加法门函数从Mongoose模式中检索array.我对这个项目使用的是nestjs，但查询是相同的:

const notifications = await this.userRepo.aggregate( [
      { $match: { _id: userId } },
      { $unwind: "$notifications" },
      { $replaceRoot: { newRoot: '$notifications' } }
] );

这里的问题是，每次我得到一个空array.无论文档中包含什么内容.

以下是一个文档示例:

{
  _id: new ObjectId("6471fe4a0045e48a0c6193ba"),
  gateways: [
    {
      _id: '5231db1f-b79a-4dc3-a387-6f08ad7b6857',
      name: 'Babylon Dev',
      right: 'owner'
    }
  ],
  __v: 0,
  notifications: [
    {
      type: 'confirm',
      title: 'Gateway whitelist request!',
      description: '6471fe4a0045e48a0c6193ba wants to share data from gateway 5231db1f-b79a-4dc3-a387-6f08ad7b6857 with you.',
      actions: [Array],
      from: '6471fe4a0045e48a0c6193ba',
      subject: '5231db1f-b79a-4dc3-a387-6f08ad7b6857',
      status: 'unread',
      _id: new ObjectId("64b6791adbf7bb6eaa528cf2")
    }
  ]
}

有没有人能告诉我，我把这个设在哪里错了？

我想要的结果是获得通知数组:

[
    {
      type: 'confirm',
      title: 'Gateway whitelist request!',
      description: '6471fe4a0045e48a0c6193ba wants to share data from gateway 5231db1f-b79a-4dc3-a387-6f08ad7b6857 with you.',
      actions: [Array],
      from: '6471fe4a0045e48a0c6193ba',
      subject: '5231db1f-b79a-4dc3-a387-6f08ad7b6857',
      status: 'unread',
      _id: new ObjectId("64b6791adbf7bb6eaa528cf2")
    }
  ]

此外，获取/更新/删除notifications数组中的一个元素也会有所帮助.