[{_id:"3df61406-a65c-480d-b258-85786caa871e","model":["nnn","mmm"],childrens:["2a865da0-fbe1-4842-954d-8c7b527f8bd1","8d06e6af-5f68-4559-9712-706afed5c0db"]},{_id:"2a865da0-fbe1-4842-954d-8c7b527f8bd1","model":["nnn","mmm"],childrens:["4f84d69a-94da-4219-a85d-0293a615da8d","5e55c16f-1b39-48ca-8f79-7acc373dca13"]},{_id:"4f84d69a-94da-4219-a85d-0293a615da8d","model":["nnn","mmm"],childrens:[]},{_id:"5e55c16f-1b39-48ca-8f79-7acc373dca13","model":["nnn","mmm"],childrens:["fb47003b-8b9f-4c1c-bc6c-cf51c0dbb8bc"]},{_id:"8d06e6af-5f68-4559-9712-706afed5c0db","model":["nnn","mmm"],childrens:[]},{_id:"fb47003b-8b9f-4c1c-bc6c-cf51c0dbb8bc","model":["nnn","mmm"],childrens:[]}]

db.collection.aggregate([{$unwind:"$childrens"},{$graphLookup:{from:"collection",startWith:"$childrens",connectFromField:"childrens",connectToField:"_id",as:"childrensList"}}])