db={"ids":[{"_id":"6001"},{"_id":"6002"},{"_id":"6003"}],"data":[{"foreignKey":"6001","createdAt":"2020-08-30T12:00:00.948Z","updatedAt":"2020-08-30T16:00:00.948Z",},{"foreignKey":"6001","createdAt":"2020-08-29T12:00:00.948Z","updatedAt":"2020-08-30T16:00:00.948Z",},{"foreignKey":"6002","createdAt":"2020-08-30T09:00:00.948Z","updatedAt":"2020-08-30T21:00:00.948Z",}]}

db.ids.aggregate([{"$lookup":{"from":"data","localField":"_id","foreignField":"foreignKey","as":"data"}},{"$project":{"data":{$cond:{if:{$gte:[{$size:"$data"},1]},then:true,else:false}}}},{$group:{"_id":"null",data:{"$addToSet":{"k":"$$ROOT._id","v":"$$ROOT.data"}}}},{"$project":{"_id":0,"data":{"$arrayToObject":"$data"}}},{$replaceRoot:{newRoot:{"$mergeObjects":"$data"}}}])