Mongodb查询与if条件匹配形成多个空值字段

我有一个json . sender.client和receiver.client不能总是值

下面是示例json的一部分:

{"sender" : {
        "id" : "5d95", 
        "name" : "Name1", 
        "phone" : "123456",
        "client" : "spec1"
    }, 
    "receiver" : {
        "id" : "5d95683", 
        "name" : "name2", 
        "phone" : "342235", 
        "client" : "spec1"
    }
}

{"sender" : {
        "id" : "52fes", 
        "name" : "Name2", 
        "phone" : "3334321",
        "client" : "spec2"
    }, 
    "receiver" : {
        "id" : "5efse", 
        "name" : "name3", 
        "phone" : "7353344", 
        "client" : "spec1"
    }
}

我的目标是过滤条件 (sender.client=spec1或receiver.client=spec1) 然后显示所有字段,即如果客户端名称匹配,则必须显示其他必需字段。我一直在尝试$project和$match,但是match不使用$cond,所以我选择了$eq的替代路径,但这并不能帮助我过滤掉我的需求。以下是我的代码:

    { 
        "$project" : {
            "sendername" : {
                "$cond" : {
                    "if" : {
                        "$eq" : [
                            "$sender.client", 
                            "spec1"
                        ]
                    }, 
                    "then" : "$sender.name", 
                    "else" : 0.0
                }
            }, 
            "sendername1" : {
                "$cond" : {
                    "if" : {
                        "$eq" : [
                            "$receiver.client", 
                            "spec1"
                        ]
                    }, 
                    "then" : "$receiver.name", 
                    "else" : 0.0
                }
            }
        }
    }

我想在$eq的空间中使用$match。我该如何完成?