[{"title":"newwww","message":[{"_id":ObjectId("606d6ea237c2544324925c61"),"text":"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","user_id":null,"user_full_name":null,"user_mobile_number":null,"submit_date":{"$date":"2021-04-07T08:32:16.093Z"}},{"_id":ObjectId("606d6edc546feebf508d75f9"),"text":"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","user_id":null,"user_full_name":null,"user_mobile_number":"9653256482","submit_date":{"$date":"2021-04-07T08:35:40.881Z"}}],"user_mobile_number":"9652351489",}]

db.collection.aggregate([{"$project":{"message":{"$map":{input:"$message","as":"message","in":{"$cond":[{"$eq":["$$message.user_mobile_number",null]},{is_admin:false},{is_admin:true}]}}}}}])