[{"title":"A","reference":["2","3"],"id":"1","author":["Doraemon"]},{"title":"B","reference":[],"id":"2","author":["Naruto"]}]

db.collection.aggregate([{"$lookup":{"from":"collection","localField":"reference","foreignField":"id","as":"selfJoin"}},{$addFields:{reference:"$selfJoin.title"}},{$project:{selfJoin:0}}])