如何在javascript对象数组中查找或聚合对象字段（在mongodb中）？

我希望在我的mongoose模式中有一个字段contractType，它是一个对象数组，每个对象的属性authorizedBy进入第二级

contractType字段可能有许多项，我想通过在另一个名为admins的集合中查找它来了解每个授权项（我也将在下面介绍）

这是我的管理员收藏

const adminSchema = new Schema(
  {
    firstName: String,
    lastName: String,
    role: String
  },
  {
    timestamps: true,
    versionKey: false,
  },
)

我在专业模式mongodb compass中有这个：

{
  "_id": ObjectId("6009a0d0874f0900086ee0ce"),
  "firstName": "xxxx",
  "gender": "NOT_SPECIFIED",
  "contractType": [
    {
      "authorizedBy": ObjectId("5fad90665d963cbbbd4a6580"),
      "document": "document 1"
    },
    {
      "authorizedBy": ObjectId("5fad90665d963cbbbd4a6580"),
      "document": "document 2"
    }
  ]
}

这是管理员集合的管理员（adminSchema）：

我会得到下面这样的响应，另外，我希望获得对象的所有字段（大约20个），而不是手动添加每个字段，就像javascript中的扩展运算符（…项）

{
  "_id": ObjectId("6009a0d0874f0900086ee0ce"),
  "firstName": "xxxx",
  "contractType": [
    {
      "authorizedBy": {
        "_id": "5fad90665d963cbbbd4a6580",
        "firstName": "firstname",
        "lastName": "lastname",
        "role": "SAM"
      },
      "document": "document 1"
    },
    {
      "authorizedBy": {
        "_id": "5fad90665d963cbbbd4a6580",
        "firstName": "firstname",
        "lastName": "lastname",
        "role": "SAM"
      },
      "document": "document 2"
    }
  ]
}

我在mongo compass中试过这个

[
  {
    '$match': {
      '_id': new ObjectId('6009a0d0874f0900086ee0ce')
    }
  }, {
    '$unwind': {
      'path': '$contractType'
    }
  }, {
    '$lookup': {
      'from': 'admins', 
      'localField': 'contractType.authorizedBy', 
      'foreignField': '_id', 
      'as': 'contractType.authorizedBy'
    }
  }, {
    '$unwind': {
      'path': '$contractType.authorizedBy'
  }
  }, {
    $group': {
      '_id': '$_id'
    }
  }
]

---

但我不知道如何将其余元素（大约20个）放在同一个对象中：（

您所做的几乎是正确的

db.professionalSchema.aggregate([
  {"$match": {"_id": ObjectId("6009a0d0874f0900086ee0ce") } },
  {"$unwind": {"path": "$contractType" }},
  {
    "$lookup": {
      "from": "adminSchema",
      "localField": "contractType.authorizedBy",
      "foreignField": "_id",
      "as": "contractType.authorizedBy"
    }
  },
  {
    "$addFields": {
      "contractType.authorizedBy": {
        $ifNull: [
          {  $arrayElemAt: [ "$contractType.authorizedBy", 0 ] },
          ""
        ]
      }
    }
  },
  {
    "$group": {
      "_id": "$_id",
      "firstName": { $first: "$firstName" },
      "gender": { $first: "$gender"},
      contractType: { $push: "$contractType" }
    }
  }
])

---

工作

你能分享示例输入和预期输出吗？我用这些信息更新问题：但是如果在我的专业模式中，我有20多个字段，其中一些字段嵌入了文档…有没有办法将所有属性传递给组的结果？比如javascript中的spread操作符{…items}

[
  {
    '$match': {
      '_id': new ObjectId('6009a0d0874f0900086ee0ce')
    }
  }, {
    '$unwind': {
      'path': '$contractType'
    }
  }, {
    '$lookup': {
      'from': 'admins', 
      'localField': 'contractType.authorizedBy', 
      'foreignField': '_id', 
      'as': 'contractType.authorizedBy'
    }
  }, {
    '$unwind': {
      'path': '$contractType.authorizedBy'
  }
  }, {
    $group': {
      '_id': '$_id'
    }
  }
]

db.professionalSchema.aggregate([
  {"$match": {"_id": ObjectId("6009a0d0874f0900086ee0ce") } },
  {"$unwind": {"path": "$contractType" }},
  {
    "$lookup": {
      "from": "adminSchema",
      "localField": "contractType.authorizedBy",
      "foreignField": "_id",
      "as": "contractType.authorizedBy"
    }
  },
  {
    "$addFields": {
      "contractType.authorizedBy": {
        $ifNull: [
          {  $arrayElemAt: [ "$contractType.authorizedBy", 0 ] },
          ""
        ]
      }
    }
  },
  {
    "$group": {
      "_id": "$_id",
      "firstName": { $first: "$firstName" },
      "gender": { $first: "$gender"},
      contractType: { $push: "$contractType" }
    }
  }
])