In mongodb know index of array element matched with $in operator?

Question

I am using aggregation with mongoDB now i am facing a problem here, i am trying to match my documents which are present in my input array by using $in operator. Now i want t

Answer 1

//$match,$in,$and

    $match:{
        $and:[        
        {"uniqueID":{$in:["CONV0001"]}},
        {"parentID":{$in:["null"]}},
        ]
       }
   }])