ToDoc 會將 struct 轉為 bson 格式 example: type Sample struct { Id string `bson:"-"` Title string `bson:"title,omitempty"` ExpireAt time.Time `bson:"expireAt,omitempty"` } s := Sample{ ExpireAt: time.Now() } m, _ := ToDoc(s) // m = &map[expireAt:1641516571365] fmt.Println(m).