Mongoose 以自定义格式聚合结果答案

【问题标题】：Mongoose aggregate result in custom formatMongoose 以自定义格式聚合结果
【发布时间】：2018-08-01 17:26:58
【问题描述】：

我正在将 mongodb 与 mongoose 一起使用，并尝试在我的回调中重现这种格式，如下所示：

{
warning:[ {
    "_id": "5a8dcdbcadb65b484e888091",
    "application_name": "teste",
    "created_at": "2018-02-02T23:55:06.000Z",
    "log_identifier": "1"
  }, {
    "_id": "5a8dcdbcadb65b484e888091",
    "application_name": "teste",
    "created_at": "2018-02-02T23:55:06.000Z",
    "log_identifier": "1"
  }],
error:[ {
    "_id": "5a8dcdbcadb65b484e888091",
    "application_name": "teste",
    "created_at": "2018-02-02T23:55:06.000Z",
    "log_identifier": "1"
  }, {
    "_id": "5a8dcdbcadb65b484e888091",
    "application_name": "teste",
    "created_at": "2018-02-02T23:55:06.000Z",
    "log_identifier": "1"
  }]
}

这是我的模型：

var logSchema = new Schema({
    application_name: String,
    file_name: String,
    type: String,
    created_at: Date,
    log_identifier: String,
    environment: String
 });

我正在使用聚合方法按类型设置类型和分组，如下所示：

LogModel.aggregate([
        {
            "$unwind": "$type"
        }, {

            $group: {
                "_id": {
                    type: "$type"
                },

                "Warning": {

                    "$push": {
                        "$cond": {
                            if: {
                                $eq: ["$type", "Warning"]
                            },
                            then: {
                                "_id": "$_id",
                                "application_name": "$application_name",
                                "created_at": "$created_at",
                                "log_identifier": "$log_identifier",
                                "enviroment": "$enviroment"
                            },
                            else: false,
                        }
                    }
                },
                "Error": {

                    "$push": {
                        "$cond": {
                            if: {
                                $eq: ["$type", "Error"]
                            },
                            then: {
                                "_id": "$_id",
                                "application_name": "$application_name",
                                "created_at": "$created_at",
                                "log_identifier": "$log_identifier",
                                "enviroment": "$enviroment"
                            },
                            else: false,
                        }
                    }
                }
            }
        }


    ], function (err, logs) {
        if (err) reject(err);
        else resolve(logs)
    });

但我的结果是

[
  {
    "_id": {
     "type": "Error"
    },
    "Warning": [
  false
],
 "Error": [
   {
     "_id": "5a8dd312c681334d558e6169",
     "application_name": "teste",
     "created_at": "2018-02-02T23:55:06.000Z",
     "log_identifier": "1"
   }
 ]
  },
  {
    "_id": {
      "type": "Warning"
    },
    "Warning": [
      {
        "_id": "5a7b6a36a5799090cf76bc4c",
        "application_name": "teste",
        "created_at": "2018-02-02T23:37:06.000Z",
        "log_identifier": "1"
      },
      {
        "_id": "5a7b6a49a5799090cf76bc4d",
        "application_name": "teste",
        "created_at": "2018-02-02T23:55:06.000Z",
        "log_identifier": "1"
      },
      {
        "_id": "5a8dcdbcadb65b484e888091",
        "application_name": "teste",
        "created_at": "2018-02-02T23:55:06.000Z",
        "log_identifier": "1"
      }
    ],
    "Error": [
      false,
      false,
      false
    ]
  }
]

我不想要具有错误值的字段，并且我不知道其他方法可以重现我想要的内容。

谁能帮帮我？

【问题讨论】：

标签： javascript node.js mongodb mongoose aggregation-framework

【解决方案1】：

你可以在 3.4 版本中重写你的聚合。

$group 按类型并推送每种类型的值。 $replaceRoot 和 $arrayToObject 输出命名键。

LogModel.aggregate([
  {"$group":{
    "_id":"$type",
    "data":{
      "$push":{
        "_id":"$_id",
        "application_name":"$application_name",
        "created_at":"$created_at",
        "log_identifier":"$log_identifier",
        "enviroment":"$enviroment"
      }
    }
  }},
  {"$replaceRoot":{
    "newRoot":{
      "$let":{
        "vars":{"array":[["$_id","$data"]]},
        "in":{"$arrayToObject":"$$array"}}
    }
  }}
])

【讨论】：