db={"user":[{"_id":1,"name":"Sam"}],"meal":[{"user":1,"content":"apple","createdAt":ISODate("2021-09-01T11:23:25.184Z")},{"user":1,"content":"orange","createdAt":ISODate("2021-09-01T11:23:25.184Z")},{"user":1,"content":"pie","createdAt":ISODate("2021-09-02T11:23:25.184Z")}],"activity":[{"user":1,"content":"baseball","createdAt":ISODate("2021-09-01T11:23:25.184Z")}],"role":[{"user":1,"content":"admin","createdAt":ISODate("2021-09-01T11:23:25.184Z")}]}

db.user.aggregate([{"$match":{_id:1}},{"$lookup":{"from":"meal","localField":"_id","foreignField":"user","pipeline":[{"$set":{"from":"meal"}}],"as":"meal_docs"}},{"$lookup":{"from":"activity","localField":"_id","foreignField":"user","pipeline":[{"$set":{"from":"activity"}}],"as":"activity_docs"}},{"$lookup":{"from":"role","localField":"_id","foreignField":"user","pipeline":[{"$set":{"from":"role"}}],"as":"role_docs"}},{$project:{user:"$name",items:{$concatArrays:["$activity_docs","$meal_docs","$role_docs"]}}},{"$unwind":"$items"},{$project:{createdAt:{$dateTrunc:{"date":"$items.createdAt","unit":"day"}},content:"$items.content",from:"$items.from"}},{"$group":{"_id":{"createdAt":"$createdAt","from":"$from"},"list":{"$push":"$$ROOT.content"}}},{"$group":{"_id":"$_id.createdAt","documents":{"$push":{k:"$$ROOT._id.from",v:"$$ROOT.list"}}}},{"$project":{documents:{$arrayToObject:"$documents"}}},{"$group":{"_id":1,"history":{"$push":{date:"$$ROOT._id",activity:"$$ROOT.documents.activity",meal:"$$ROOT.documents.meal",role:"$$ROOT.documents.role"}}}}])