来自mongo shell和nodejs应用程序的2个不同输出

Question

我在mongo shell和从nodejs应用程序获取响应时获得了不同的输出结果。

请注意我是mongoose作为mongodb的nodejs驱动程序

下面给出的代码。

_id:ObjectId("55eab3cb358c513439c3ce5d")
building_id:"55eab32b358c513439c3ce5c";
flat_tenants:[{
          "_id": {
            "tenant_id": "",
            "agreement_start_date": null,
            "agreement_end_date": null,
            "rent_amt": 10000,
            "rent_cycle": 7,
            "advance_proof": null,
            "id_proof": null,
            "other_terms": null,
            "is_active": "false",
            "_id": "55eac5db5e1ddb87104a7865",
            "rent": []
          }
        },
        {
          "_id": {
            "tenant_id": "geo@g.org",
            "agreement_start_date": null,
            "agreement_end_date": null,
            "rent_amt": 10000,
            "rent_cycle": 7,
            "advance_proof": null,
            "id_proof": null,
            "other_terms": null,
            "is_active": "true",
            "_id": "55eac6065e1ddb87104a7866",
            "rent": []
          }
        },
        {
          "_id": {
            "tenant_id": "geo2@g.org",
            "agreement_start_date": null,
            "agreement_end_date": null,
            "rent_amt": 10000,
            "rent_cycle": 7,
            "advance_proof": null,
            "id_proof": null,
            "other_terms": null,
            "is_active": "false",
            "_id": "55ead263232fe9585a86bb7f",
            "rent": []
          }
        },
        {
          "_id": {
            "tenant_id": "geo3@g.org",
            "agreement_start_date": null,
            "agreement_end_date": null,
            "rent_amt": 10000,
            "rent_cycle": 7,
            "advance_proof": null,
            "id_proof": null,
            "other_terms": null,
            "is_active": "true",
            "_id": "55eb434f1d844381555c41c0",
            "rent": []
          }
        }
]
}

mongo shell的输出：

"1" : {
                "tenant_id" : "geo2@g.org",
                "agreement_start_date" : null,
                "agreement_end_date" : null,
                "rent_amt" : 10000,
                "rent_cycle" : 7,
                "advance_proof" : null,
                "id_proof" : null,
                "other_terms" : null,
                "is_active" : "false",
                "_id" : ObjectId("55ead263232fe9585a86bb7f"),
                "rent" : [ ]
        }

通过nodejs app输出：

{
      "_id": {
        "tenant_id": "",
        "agreement_start_date": null,
        "agreement_end_date": null,
        "rent_amt": 10000,
        "rent_cycle": 7,
        "advance_proof": null,
        "id_proof": null,
        "other_terms": null,
        "is_active": "false",
        "_id": "55eac5db5e1ddb87104a7865",
        "rent": []
      }
    },
    {
      "_id": {
        "tenant_id": "geo@g.org",
        "agreement_start_date": null,
        "agreement_end_date": null,
        "rent_amt": 10000,
        "rent_cycle": 7,
        "advance_proof": null,
        "id_proof": null,
        "other_terms": null,
        "is_active": "true",
        "_id": "55eac6065e1ddb87104a7866",
        "rent": []
      }
    },
    {
      "_id": {
        "tenant_id": "geo2@g.org",
        "agreement_start_date": null,
        "agreement_end_date": null,
        "rent_amt": 10000,
        "rent_cycle": 7,
        "advance_proof": null,
        "id_proof": null,
        "other_terms": null,
        "is_active": "false",
        "_id": "55ead263232fe9585a86bb7f",
        "rent": []
      }
    },
    {
      "_id": {
        "tenant_id": "geo3@g.org",
        "agreement_start_date": null,
        "agreement_end_date": null,
        "rent_amt": 10000,
        "rent_cycle": 7,
        "advance_proof": null,
        "id_proof": null,
        "other_terms": null,
        "is_active": "true",
        "_id": "55eb434f1d844381555c41c0",
        "rent": []
      }
    }

mongodb代码：

flats.aggregate({$match:{building_id: "55eab32b358c513439c3ce5c", _id:ObjectId("55eab3cb358c513439c3ce5d")}},
    {$unwind:"$flat_tenant"},
    {$match:{"flat_tenant._id": ObjectId("55eac5db5e1ddb87104a7865") }}, 
    { $project: { _id: 0, _id: "$flat_tenant" } } ).exec(function(err, tenantDetails1) {

有人可以帮我弄清楚为什么我会遇到这个问题。