如何在mongodb中将我的对象转换为数组

Question

我的数据看起来像这样

{
    "_id": ObjectId("57ef642fd4f27bb41b697314"),
    "compCode": "0001",
    "menuName": "Cash",
    "menuDesc": "Cash Module",
    "formName": "",
    "search": "n",
    "effStatus": "A",
    "dispSeq": "20",
    "subMenu1": [{
        "menuName": "Cash Vouchers",
        "menuDesc": "Vouchers",
        "formName": "",
        "search": "n",
        "effStatus": "A",
        "dispSeq": "10",
        "subMenu2": {
            "menuName": "Cash Voucher",
            "menuDesc": "Maintain Cash Voucher",
            "formName": "cavoucher",
            "search": "n",
            "effStatus": "A",
            "dispSeq": "10"
        }
    }]
};

我已经在上面给出了我的数据这个结果我已经使用mongodb聚合查询实现了这个结果但我希望我的submenu2必须在数组中而不是对象这是可能的当我尝试通过这样做“subMenu1.subMenu2”对subMenu2进行分组时： {“$ addToSet”：“$ subMenu1”}它显示我无法使用的错误。在小组声明中，我怎么能这样做我的预期结果是

{
    "_id": ObjectId("57ef642fd4f27bb41b697314"),
    "compCode": "0001",
    "menuName": "Cash",
    "menuDesc": "Cash Module",
    "formName": "",
    "search": "n",
    "effStatus": "A",
    "dispSeq": "20",
    "subMenu1": [{
        "menuName": "Cash Vouchers",
        "menuDesc": "Vouchers",
        "formName": "",
        "search": "n",
        "effStatus": "A",
        "dispSeq": "10",
        "subMenu2": [{
            "menuName": "Cash Voucher",
            "menuDesc": "Maintain Cash Voucher",
            "formName": "cavoucher",
            "search": "n",
            "effStatus": "A",
            "dispSeq": "10"
        }]
    }]
};

和我的汇总查询

db.sys_mainmenu.aggregate([
    {$unwind:"$subMenu1"}, 
    {$unwind:"$subMenu1.subMenu2"},
    {$match:{"subMenu1.subMenu2.formName":{"$in":"cavoucher","systranslate"]}}},
 { "$group": { 

                    "_id": "$_id",
                    "compCode":{"$first":"$compCode"},
                     "menuName":{"$first":"$menuName"}, 
                    "menuDesc": {"$first":"$menuDesc"}, 
                    "formName": {"$first":"$formName"}, 
                    "search": {"$first":"$search"}, 
                    "effStatus":{"$first": "$effStatus"}, 
                    "dispSeq": {"$first":"$dispSeq"},
                    "subMenu1": { "$addToSet": "$subMenu1" }

                }
    }

]）