diff --git a/Fk/Cheat/FreeAssign.qml b/Fk/Cheat/FreeAssign.qml
index 1ae3fb87..4b41e9e6 100644
--- a/Fk/Cheat/FreeAssign.qml
+++ b/Fk/Cheat/FreeAssign.qml
@@ -110,7 +110,7 @@ Item {
   }
 
   function load() {
-    let packs = JSON.parse(Backend.callLuaFunction("GetAllGeneralPack", []));
+    const packs = JSON.parse(Backend.callLuaFunction("GetAllGeneralPack", []));
     packs.forEach((name) => packages.append({ name: name }));
   }
 
diff --git a/Fk/Cheat/PlayerDetail.qml b/Fk/Cheat/PlayerDetail.qml
index e281fb50..c649ec21 100644
--- a/Fk/Cheat/PlayerDetail.qml
+++ b/Fk/Cheat/PlayerDetail.qml
@@ -97,13 +97,13 @@ Flickable {
     screenName.text = "";
     skillDesc.text = "";
 
-    let id = extra_data.photo.playerid;
+    const id = extra_data.photo.playerid;
     if (id == 0) return;
     root.pid = id;
 
     screenName.text = extra_data.photo.screenName;
 
-    let data = JSON.parse(Backend.callLuaFunction("GetPlayerSkills", [id]));
+    const data = JSON.parse(Backend.callLuaFunction("GetPlayerSkills", [id]));
     data.forEach(t => {
       skillDesc.append("<b>" + Backend.translate(t.name) + "</b>: " + t.description)
     });
diff --git a/Fk/Common/LogEdit.qml b/Fk/Common/LogEdit.qml
index e9607baa..44491f80 100644
--- a/Fk/Common/LogEdit.qml
+++ b/Fk/Common/LogEdit.qml
@@ -44,7 +44,7 @@ ListView {
   }
 
   function append(text) {
-    let autoScroll = root.currentIndex === logModel.count - 1;
+    const autoScroll = root.currentIndex === logModel.count - 1;
     logModel.append({ logText: text });
     if (autoScroll) {
       root.currentIndex = logModel.count - 1;
diff --git a/Fk/LobbyElement/RoomGeneralSettings.qml b/Fk/LobbyElement/RoomGeneralSettings.qml
index b49a5297..1cfa2a0d 100644
--- a/Fk/LobbyElement/RoomGeneralSettings.qml
+++ b/Fk/LobbyElement/RoomGeneralSettings.qml
@@ -57,7 +57,7 @@ Flickable {
         }
 
         onCurrentIndexChanged: {
-          let data = gameModeList.get(currentIndex);
+          const data = gameModeList.get(currentIndex);
           playerNum.from = data.minPlayer;
           playerNum.to = data.maxPlayer;
 
@@ -188,7 +188,7 @@ Flickable {
     }
 
     Component.onCompleted: {
-      let mode_data = JSON.parse(Backend.callLuaFunction("GetGameModes", []));
+      const mode_data = JSON.parse(Backend.callLuaFunction("GetGameModes", []));
       let i = 0;
       for (let d of mode_data) {
         gameModeList.append(d);
diff --git a/Fk/LobbyElement/RoomPackageSettings.qml b/Fk/LobbyElement/RoomPackageSettings.qml
index 530a756f..7e218745 100644
--- a/Fk/LobbyElement/RoomPackageSettings.qml
+++ b/Fk/LobbyElement/RoomPackageSettings.qml
@@ -45,9 +45,9 @@ Flickable {
           enabled: orig_name !== "test_p_0"
 
           onCheckedChanged: {
-            let packs = config.disabledPack;
+            const packs = config.disabledPack;
             if (checked) {
-              let idx = packs.indexOf(orig_name);
+              const idx = packs.indexOf(orig_name);
               if (idx !== -1) packs.splice(idx, 1);
             } else {
               packs.push(orig_name);
@@ -76,9 +76,9 @@ Flickable {
           checked: pkg_enabled
 
           onCheckedChanged: {
-            let packs = config.disabledPack;
+            const packs = config.disabledPack;
             if (checked) {
-              let idx = packs.indexOf(orig_name);
+              const idx = packs.indexOf(orig_name);
               if (idx !== -1) packs.splice(idx, 1);
             } else {
               packs.push(orig_name);
@@ -90,7 +90,7 @@ Flickable {
   }
 
   Component.onCompleted: {
-    let g = JSON.parse(Backend.callLuaFunction("GetAllGeneralPack", []));
+    const g = JSON.parse(Backend.callLuaFunction("GetAllGeneralPack", []));
     for (let orig of g) {
       gpacklist.append({
         name: Backend.translate(orig),
@@ -99,7 +99,7 @@ Flickable {
       });
     }
 
-    let c = JSON.parse(Backend.callLuaFunction("GetAllCardPack", []));
+    const c = JSON.parse(Backend.callLuaFunction("GetAllCardPack", []));
     for (let orig of c) {
       cpacklist.append({
         name: Backend.translate(orig),
diff --git a/Fk/Logic.js b/Fk/Logic.js
index c7c19afd..0b5577c4 100644
--- a/Fk/Logic.js
+++ b/Fk/Logic.js
@@ -105,7 +105,7 @@ callbacks["EnterRoom"] = (jsonData) => {
 
 callbacks["UpdateRoomList"] = (jsonData) => {
   const current = mainStack.currentItem;  // should be lobby
-  if (mainStack.currentItem === lobby) {
+  if (mainStack.depth === 2) {
     current.roomModel.clear();
     JSON.parse(jsonData).forEach(function (room) {
       current.roomModel.append({
@@ -122,7 +122,7 @@ callbacks["UpdateRoomList"] = (jsonData) => {
 
 callbacks["UpdatePlayerNum"] = (j) => {
   const current = mainStack.currentItem;  // should be lobby
-  if (mainStack.currentItem === lobby) {
+  if (mainStack.depth === 2) {
     const data = JSON.parse(j);
     const l = data[0];
     const s = data[1];
diff --git a/Fk/Pages/CardsOverview.qml b/Fk/Pages/CardsOverview.qml
index 115c1d11..6ca24b63 100644
--- a/Fk/Pages/CardsOverview.qml
+++ b/Fk/Pages/CardsOverview.qml
@@ -72,7 +72,7 @@ Item {
       }
 
       Component.onCompleted: {
-        let data = modelData;
+        const data = modelData;
         if (!data.cards) {
           name = data.name;
           suit = data.suit;
@@ -113,15 +113,15 @@ Item {
       easing.type: Easing.InOutQuad
     }
     onFinished: {
-      let pkg = [listView.model.get(listView.currentIndex).name];
-      let idList = JSON.parse(Backend.callLuaFunction("GetCards", pkg));
-      let cardList = idList.map(id => JSON.parse(Backend.callLuaFunction
+      const pkg = [listView.model.get(listView.currentIndex).name];
+      const idList = JSON.parse(Backend.callLuaFunction("GetCards", pkg));
+      const cardList = idList.map(id => JSON.parse(Backend.callLuaFunction
         ("GetCardData",[id])));
 
-      let groupedCardList = [];
+      const groupedCardList = [];
       let groupedCards = {};
       cardList.forEach(c => {
-        let name = c.name;
+        const name = c.name;
         if (!groupedCards[name]) {
           groupedCardList.push(name);
           groupedCards[name] = [];
@@ -133,9 +133,9 @@ Item {
         });
       });
 
-      let model = [];
+      const model = [];
       groupedCardList.forEach(name => {
-        let cards = groupedCards[name];
+        const cards = groupedCards[name];
         if (cards.length === 1) {
           model.push({
             name: name,
@@ -192,7 +192,7 @@ Item {
     property int cid: 1
     property var cards
     function updateCard() {
-      let data = JSON.parse(Backend.callLuaFunction("GetCardData", [cid]));
+      const data = JSON.parse(Backend.callLuaFunction("GetCardData", [cid]));
       const suitTable = {
         spade: "♠", heart: '<font color="red">♥</font>',
         club: "♣", diamond: '<font color="red">♦</font>',
@@ -226,7 +226,7 @@ Item {
       cardText.clear();
       cardText.append(Backend.translate(":" + data.name));
 
-      let skills = JSON.parse(Backend.callLuaFunction
+      const skills = JSON.parse(Backend.callLuaFunction
         ("GetCardSpecialSkills", [cid]));
       if (skills.length > 0) {
         cardText.append("<br/>" + Backend.translate("Special card skills:"));
@@ -299,7 +299,7 @@ Item {
 
   function loadPackages() {
     if (loaded) return;
-    let packs = JSON.parse(Backend.callLuaFunction("GetAllCardPack", []));
+    const packs = JSON.parse(Backend.callLuaFunction("GetAllCardPack", []));
     packs.forEach((name) => packages.append({ name: name }));
     loaded = true;
   }
diff --git a/Fk/Pages/Danmaku.qml b/Fk/Pages/Danmaku.qml
index 1855a2c1..a2f76236 100644
--- a/Fk/Pages/Danmaku.qml
+++ b/Fk/Pages/Danmaku.qml
@@ -13,8 +13,8 @@ Item {
     if (!newTxtAvailable || stashedTxt.length === 0) {
       return;
     }
-    let t = stashedTxt.splice(0, 1)[0];
-    let obj = txtComponent.createObject(root, { text: t });
+    const t = stashedTxt.splice(0, 1)[0];
+    const obj = txtComponent.createObject(root, { text: t });
     obj.finished.connect(() => obj.destroy());
     obj.start();
   }
diff --git a/Fk/Pages/GeneralsOverview.qml b/Fk/Pages/GeneralsOverview.qml
index 8cc0785d..e49b0374 100644
--- a/Fk/Pages/GeneralsOverview.qml
+++ b/Fk/Pages/GeneralsOverview.qml
@@ -150,7 +150,7 @@ Item {
     property string general: "caocao"
     function updateGeneral() {
       detailGeneralCard.name = general;
-      let data = JSON.parse(Backend.callLuaFunction("GetGeneralDetail", [general]));
+      const data = JSON.parse(Backend.callLuaFunction("GetGeneralDetail", [general]));
       generalText.clear();
       data.skill.forEach(t => {
         generalText.append("<b>" + Backend.translate(t.name) + "</b>: " + t.description)
@@ -233,7 +233,7 @@ Item {
 
   function loadPackages() {
     if (loaded) return;
-    let packs = JSON.parse(Backend.callLuaFunction("GetAllGeneralPack", []));
+    const packs = JSON.parse(Backend.callLuaFunction("GetAllGeneralPack", []));
     packs.forEach((name) => packages.append({ name: name }));
     generalDetail.updateGeneral();
     loaded = true;
diff --git a/Fk/Pages/Init.qml b/Fk/Pages/Init.qml
index 8763af0c..dbefa7eb 100644
--- a/Fk/Pages/Init.qml
+++ b/Fk/Pages/Init.qml
@@ -71,7 +71,7 @@ Item {
               if (model.indexOf(editText) === -1) {
                 passwordEdit.text = "";
               } else {
-                let data = config.savedPassword[editText];
+                const data = config.savedPassword[editText];
                 screenNameEdit.text = data.username;
                 passwordEdit.text = data.shorten_password;
               }
@@ -89,7 +89,7 @@ Item {
             text: ""
             onTextChanged: {
               passwordEdit.text = "";
-              let data = config.savedPassword[server_addr.editText];
+              const data = config.savedPassword[server_addr.editText];
               if (data) {
                 if (text === data.username) {
                   passwordEdit.text = data.shorten_password;
@@ -207,7 +207,7 @@ Item {
     server_addr.onModelChanged();
     server_addr.currentIndex = server_addr.model.indexOf(config.lastLoginServer);
 
-    let data = config.savedPassword[config.lastLoginServer];
+    const data = config.savedPassword[config.lastLoginServer];
     if (data) {
       screenNameEdit.text = data.username;
       passwordEdit.text = data.shorten_password;
diff --git a/Fk/Pages/ModesOverview.qml b/Fk/Pages/ModesOverview.qml
index 677467e6..74ec3728 100644
--- a/Fk/Pages/ModesOverview.qml
+++ b/Fk/Pages/ModesOverview.qml
@@ -67,7 +67,7 @@ Item {
   }
 
   Component.onCompleted: {
-    let mode_data = JSON.parse(Backend.callLuaFunction("GetGameModes", []));
+    const mode_data = JSON.parse(Backend.callLuaFunction("GetGameModes", []));
     for (let d of mode_data) {
       modeList.append(d);
     }
diff --git a/Fk/Pages/PackageManage.qml b/Fk/Pages/PackageManage.qml
index d008250d..c093c88e 100644
--- a/Fk/Pages/PackageManage.qml
+++ b/Fk/Pages/PackageManage.qml
@@ -33,7 +33,7 @@ Item {
             text: qsTr("Enable All")
             onTriggered: {
               for (let i = 0; i < packageModel.count; i++) {
-                let name = packageModel.get(i).pkgName;
+                const name = packageModel.get(i).pkgName;
                 Pacman.enablePack(name);
               }
               updatePackageList();
@@ -43,7 +43,7 @@ Item {
             text: qsTr("Disable All")
             onTriggered: {
               for (let i = 0; i < packageModel.count; i++) {
-                let name = packageModel.get(i).pkgName;
+                const name = packageModel.get(i).pkgName;
                 Pacman.disablePack(name);
               }
               updatePackageList();
@@ -53,7 +53,7 @@ Item {
             text: qsTr("Upgrade All")
             onTriggered: {
               for (let i = 0; i < packageModel.count; i++) {
-                let name = packageModel.get(i).pkgName;
+                const name = packageModel.get(i).pkgName;
                 Pacman.upgradePack(name);
               }
               updatePackageList();
@@ -162,7 +162,7 @@ Item {
         text: qsTr("Install From URL")
         enabled: urlEdit.text !== ""
         onClicked: {
-          let url = urlEdit.text;
+          const url = urlEdit.text;
           mainWindow.busy = true;
           Pacman.downloadNewPack(url, true);
         }
@@ -172,7 +172,7 @@ Item {
 
   function updatePackageList() {
     packageModel.clear();
-    let data = JSON.parse(Pacman.listPackages());
+    const data = JSON.parse(Pacman.listPackages());
     data.forEach(e => packageModel.append({
       pkgName: e.name,
       pkgURL: e.url,
@@ -182,7 +182,7 @@ Item {
   }
 
   function downloadComplete() {
-    let idx = packageList.currentIndex;
+    const idx = packageList.currentIndex;
     updatePackageList();
     packageList.currentIndex = idx;
   }
diff --git a/Fk/Pages/Room.qml b/Fk/Pages/Room.qml
index c4d55001..f0dff654 100644
--- a/Fk/Pages/Room.qml
+++ b/Fk/Pages/Room.qml
@@ -125,7 +125,7 @@ Item {
     Text {
       x: 8; y: 8
       Component.onCompleted: {
-        let data = JSON.parse(Backend.callLuaFunction("GetRoomConfig", []));
+        const data = JSON.parse(Backend.callLuaFunction("GetRoomConfig", []));
         text = "手气卡次数：" + data.luckTime + "<br />出手时间：" + config.roomTimeout
           + "<br />选将框数：" + data.generalNum
       }
@@ -315,7 +315,7 @@ Item {
       Logic.enableTargets(card);
 
       if (typeof card === "number" && card !== -1 && roomScene.state === "playing") {
-        let skills = JSON.parse(Backend.callLuaFunction("GetCardSpecialSkills", [card]));
+        const skills = JSON.parse(Backend.callLuaFunction("GetCardSpecialSkills", [card]));
         if (JSON.parse(Backend.callLuaFunction("CanUseCard", [card, Self.id]))) {
           skills.unshift("_normal_use");
         }
@@ -532,7 +532,7 @@ Item {
 
   function activateSkill(skill_name, pressed) {
     if (pressed) {
-      let data = JSON.parse(Backend.callLuaFunction("GetInteractionOfSkill", [skill_name]));
+      const data = JSON.parse(Backend.callLuaFunction("GetInteractionOfSkill", [skill_name]));
       if (data) {
         Backend.callLuaFunction("SetInteractionDataOfSkill", [skill_name, "null"]);
         switch (data.type) {
@@ -735,9 +735,9 @@ Item {
     }
 
     for (let i = 1; i < specialCardSkills.count; i++) {
-      let item = specialCardSkills.itemAt(i);
+      const item = specialCardSkills.itemAt(i);
       if (item.checked) {
-        let ret = item.orig_text;
+        const ret = item.orig_text;
         return ret;
       }
     }
@@ -753,10 +753,10 @@ Item {
       if (specialChat(pid, raw, raw.msg.slice(1))) return;
     }
     chat.append(msg);
-    let photo = Logic.getPhoto(pid);
+    const photo = Logic.getPhoto(pid);
     if (photo === undefined) {
-      let user = raw.userName;
-      let m = raw.msg;
+      const user = raw.userName;
+      const m = raw.msg;
       danmaku.sendLog(`${user}: ${m}`);
       return;
     }
@@ -768,13 +768,13 @@ Item {
     // death audio: ~%s
     // something special: !%s:...
 
-    let time = data.time;
-    let userName = data.userName;
-    let general = Backend.translate(data.general);
+    const time = data.time;
+    const userName = data.userName;
+    const general = Backend.translate(data.general);
 
     if (msg.startsWith("!")) {
-      let splited = msg.split(":");
-      let type = splited[0].slice(1);
+      const splited = msg.split(":");
+      const type = splited[0].slice(1);
       switch (type) {
         case "Egg":
         case "GiantEgg":
@@ -800,18 +800,18 @@ Item {
           return false;
       }
     } else if (msg.startsWith("~")) {
-      let g = msg.slice(1);
-      let extension = JSON.parse(Backend.callLuaFunction("GetGeneralData", [g])).extension;
+      const g = msg.slice(1);
+      const extension = JSON.parse(Backend.callLuaFunction("GetGeneralData", [g])).extension;
       if (!config.disableMsgAudio)
         Backend.playSound("./packages/" + extension + "/audio/death/" + g);
 
-      let m = Backend.translate("~" + g);
+      const m = Backend.translate("~" + g);
       if (general === "")
         chat.append(`[${time}] ${userName}: ${m}`);
       else
         chat.append(`[${time}] ${userName}(${general}): ${m}`);
 
-      let photo = Logic.getPhoto(pid);
+      const photo = Logic.getPhoto(pid);
       if (photo === undefined) {
         danmaku.sendLog(`${userName}: ${m}`);
         return true;
@@ -820,24 +820,24 @@ Item {
 
       return true;
     } else {
-      let splited = msg.split(":");
+      const splited = msg.split(":");
       if (splited.length < 2) return false;
-      let skill = splited[0];
-      let idx = parseInt(splited[1]);
+      const skill = splited[0];
+      const idx = parseInt(splited[1]);
 
-      let data2 = JSON.parse(Backend.callLuaFunction("GetSkillData", [skill]));
+      const data2 = JSON.parse(Backend.callLuaFunction("GetSkillData", [skill]));
       if (!data2) return false;
-      let extension = data2.extension;
+      const extension = data2.extension;
       if (!config.disableMsgAudio)
         Backend.playSound("./packages/" + extension + "/audio/skill/" + skill, idx);
 
-      let m = Backend.translate("$" + skill + idx.toString());
+      const m = Backend.translate("$" + skill + idx.toString());
       if (general === "")
         chat.append(`[${time}] ${userName}: ${m}`);
       else
         chat.append(`[${time}] ${userName}(${general}): ${m}`);
 
-      let photo = Logic.getPhoto(pid);
+      const photo = Logic.getPhoto(pid);
       if (photo === undefined) {
         danmaku.sendLog(`${userName}: ${m}`);
         return true;
@@ -861,9 +861,9 @@ Item {
 
   function showDistance(show) {
     for (let i = 0; i < photoModel.count; i++) {
-      let item = photos.itemAt(i);
+      const item = photos.itemAt(i);
       if (show) {
-        let dis = Backend.callLuaFunction("DistanceTo",[Self.id, item.playerid]);
+        const dis = Backend.callLuaFunction("DistanceTo",[Self.id, item.playerid]);
         item.distance = parseInt(dis);
       } else {
         item.distance = 0;
@@ -878,9 +878,9 @@ Item {
   }
 
   function resetToInit() {
-    let datalist = [];
+    const datalist = [];
     for (let i = 0; i < photoModel.count; i++) {
-      let item = photoModel.get(i);
+      const item = photoModel.get(i);
       if (item.id > 0) {
         datalist.push({
           id: item.id,
diff --git a/Fk/Pages/RoomLogic.js b/Fk/Pages/RoomLogic.js
index 2c5ed583..7e46caa6 100644
--- a/Fk/Pages/RoomLogic.js
+++ b/Fk/Pages/RoomLogic.js
@@ -288,8 +288,8 @@ function doIndicate(from, tos) {
   for (let i = 0; i < tos.length; i++) {
     if (from === tos[i])
       continue;
-    let toItem = getPhotoOrDashboard(tos[i]);
-    let toPos = mapFromItem(toItem, toItem.width / 2, toItem.height / 2);
+    const toItem = getPhotoOrDashboard(tos[i]);
+    const toPos = mapFromItem(toItem, toItem.width / 2, toItem.height / 2);
     end.push(toPos);
   }
 
@@ -315,7 +315,7 @@ function changeSelf(id) {
   // move new selfPhoto to dashboard
   let order = new Array(photoModel.count);
   for (let i = 0; i < photoModel.count; i++) {
-    let item = photoModel.get(i);
+    const item = photoModel.get(i);
     order[item.seatNumber - 1] = item.id;
     if (item.id === Self.id) {
       dashboard.self = photos.itemAt(i);
@@ -389,7 +389,7 @@ function enableTargets(card) { // card: int | { skill: string, subcards: int[] }
   }
 
   if (candidate) {
-    let data = {
+    const data = {
       ok_enabled: false,
       enabled_targets: []
     }
@@ -866,7 +866,7 @@ callbacks["AskForMoveCardInBoard"] = (jsonData) => {
 
   const boxCards = [];
   cards.forEach(id => {
-    let d = Backend.callLuaFunction("GetCardData", [id]);
+    const d = Backend.callLuaFunction("GetCardData", [id]);
     boxCards.push(JSON.parse(d));
   });
 
@@ -1032,7 +1032,7 @@ callbacks["SetPlayerMark"] = (jsonData) => {
   const player = getPhoto(data[0]);
   const mark = data[1];
   const value = data[2] instanceof Array ? data[2] : data[2].toString();
-  if (value === 0) {
+  if (data[2] === 0) {
     player.markArea.removeMark(mark);
   } else {
     player.markArea.setMark(mark, mark.startsWith("@@") ? "" : value);
diff --git a/Fk/PhotoElement/DelayedTrickArea.qml b/Fk/PhotoElement/DelayedTrickArea.qml
index 37a630f5..0db452d9 100644
--- a/Fk/PhotoElement/DelayedTrickArea.qml
+++ b/Fk/PhotoElement/DelayedTrickArea.qml
@@ -37,7 +37,7 @@ Item {
       inputs = [inputs];
     }
     inputs.forEach(card => {
-      let v = JSON.parse(Backend.callLuaFunction("GetVirtualEquip", [parent.playerid, card.cid]));
+      const v = JSON.parse(Backend.callLuaFunction("GetVirtualEquip", [parent.playerid, card.cid]));
       if (v !== null) {
         cards.append(v);
       } else {
@@ -51,11 +51,11 @@ Item {
 
   function remove(outputs)
   {
-    let result = area.remove(outputs);
+    const result = area.remove(outputs);
     for (let i = 0; i < result.length; i++) {
-      let item = result[i];
+      const item = result[i];
       for (let j = 0; j < cards.count; j++) {
-        let icon = cards.get(j);
+        const icon = cards.get(j);
         if (icon.cid === item.cid) {
           cards.remove(j, 1);
           break;
diff --git a/Fk/PhotoElement/EquipArea.qml b/Fk/PhotoElement/EquipArea.qml
index 9de14780..ed563756 100644
--- a/Fk/PhotoElement/EquipArea.qml
+++ b/Fk/PhotoElement/EquipArea.qml
@@ -100,11 +100,11 @@ Column {
 
   function remove(outputs)
   {
-    let result = area.remove(outputs);
+    const result = area.remove(outputs);
     for (let i = 0; i < result.length; i++) {
-      let card = result[i];
+      const card = result[i];
       for (let j = 0; j < items.length; j++) {
-        let item = items[j];
+        const item = items[j];
         if (item.cid === card.cid) {
           item.reset();
           item.hide();
diff --git a/Fk/PhotoElement/LimitSkillArea.qml b/Fk/PhotoElement/LimitSkillArea.qml
index 2113f95c..4632fbdf 100644
--- a/Fk/PhotoElement/LimitSkillArea.qml
+++ b/Fk/PhotoElement/LimitSkillArea.qml
@@ -19,7 +19,7 @@ ColumnLayout {
 
   function update(skill, times) {
     for (let i = 0; i < rep.count; i++) {
-      let data = skills.get(i);
+      const data = skills.get(i);
       if (data.skillname_ === skill) {
         data.times = times;
         return;
diff --git a/Fk/PhotoElement/MarkArea.qml b/Fk/PhotoElement/MarkArea.qml
index c3a6d778..47ccd764 100644
--- a/Fk/PhotoElement/MarkArea.qml
+++ b/Fk/PhotoElement/MarkArea.qml
@@ -120,17 +120,17 @@ Item {
     let x = 0;
     let y = 0;
     let i;
-    let marks = [];
-    let long_marks = [];
+    const marks = [];
+    const long_marks = [];
     for (i = 0; i < markRepeater.count; i++) {
-      let item = markRepeater.itemAt(i);
-      let w = item.width;
+      const item = markRepeater.itemAt(i);
+      const w = item.width;
       if (w < width / 2) marks.push(item);
       else long_marks.push(item);
     }
 
     marks.concat(long_marks).forEach(item => {
-      let w = item.width;
+      const w = item.width;
       if (x === 0) {
         item.x = x; item.y = y;
 
diff --git a/Fk/RoomElement/AG.qml b/Fk/RoomElement/AG.qml
index 6466c0a9..40ac9b7a 100644
--- a/Fk/RoomElement/AG.qml
+++ b/Fk/RoomElement/AG.qml
@@ -56,7 +56,7 @@ GraphicsBox {
 
   function takeAG(g, cid) {
     for (let i = 0; i < cards.count; i++) {
-      let item = cards.get(i);
+      const item = cards.get(i);
       if (item.cid !== cid) continue;
       item.footnote = g;
       item.selectable = false;
diff --git a/Fk/RoomElement/CardArea.qml b/Fk/RoomElement/CardArea.qml
index 9f2a1e54..f35ceb19 100644
--- a/Fk/RoomElement/CardArea.qml
+++ b/Fk/RoomElement/CardArea.qml
@@ -26,7 +26,7 @@ Item {
     for (let i = 0; i < cards.length; i++) {
       for (let j = 0; j < outputs.length; j++) {
         if (outputs[j] === cards[i].cid) {
-          let state = JSON.parse(Backend.callLuaFunction("GetCardData", [cards[i].cid]));
+          const state = JSON.parse(Backend.callLuaFunction("GetCardData", [cards[i].cid]));
           cards[i].setData(state);
           result.push(cards[i]);
           cards.splice(i, 1);
@@ -56,8 +56,8 @@ Item {
 
     if (overflow) {
       // TODO: Adjust cards in multiple lines if there are too many cards
-      let xLimit = root.width - card.width;
-      let spacing = xLimit / (cards.length - 1);
+      const xLimit = root.width - card.width;
+      const spacing = xLimit / (cards.length - 1);
       for (i = 0; i < cards.length; i++) {
         card = cards[i];
         card.origX = i * spacing;
@@ -65,7 +65,7 @@ Item {
       }
     }
 
-    let parentPos = roomScene.mapFromItem(root, 0, 0);
+    const parentPos = roomScene.mapFromItem(root, 0, 0);
     for (i = 0; i < cards.length; i++) {
       card = cards[i];
       card.origX += parentPos.x;
diff --git a/Fk/RoomElement/CardItem.qml b/Fk/RoomElement/CardItem.qml
index 2cea771e..2a6fc2a6 100644
--- a/Fk/RoomElement/CardItem.qml
+++ b/Fk/RoomElement/CardItem.qml
@@ -257,7 +257,7 @@ Item {
 
   function toData()
   {
-    let data = {
+    const data = {
       cid: cid,
       name: name,
       suit: suit,
diff --git a/Fk/RoomElement/Dashboard.qml b/Fk/RoomElement/Dashboard.qml
index 55247b1e..02be4b6d 100644
--- a/Fk/RoomElement/Dashboard.qml
+++ b/Fk/RoomElement/Dashboard.qml
@@ -69,32 +69,32 @@ RowLayout {
   }
 
   function expandPile(pile) {
-    let expanded_pile_names = Object.keys(expanded_piles);
+    const expanded_pile_names = Object.keys(expanded_piles);
     if (expanded_pile_names.indexOf(pile) !== -1)
       return;
 
-    let component = Qt.createComponent("../RoomElement/CardItem.qml");
-    let parentPos = roomScene.mapFromItem(self, 0, 0);
+    const component = Qt.createComponent("../RoomElement/CardItem.qml");
+    const parentPos = roomScene.mapFromItem(self, 0, 0);
 
     expanded_piles[pile] = [];
     if (pile === "_equip") {
-      let equips = self.equipArea.getAllCards();
+      const equips = self.equipArea.getAllCards();
       equips.forEach(data => {
         data.x = parentPos.x;
         data.y = parentPos.y;
-        let card = component.createObject(roomScene, data);
+        const card = component.createObject(roomScene, data);
         card.footnoteVisible = true;
         card.footnote = Backend.translate("$Equip");
         handcardAreaItem.add(card);
       })
       handcardAreaItem.updateCardPosition();
     } else {
-      let ids = JSON.parse(Backend.callLuaFunction("GetPile", [self.playerid, pile]));
+      const ids = JSON.parse(Backend.callLuaFunction("GetPile", [self.playerid, pile]));
       ids.forEach(id => {
-        let data = JSON.parse(Backend.callLuaFunction("GetCardData", [id]));
+        const data = JSON.parse(Backend.callLuaFunction("GetCardData", [id]));
         data.x = parentPos.x;
         data.y = parentPos.y;
-        let card = component.createObject(roomScene, data);
+        const card = component.createObject(roomScene, data);
         card.footnoteVisible = true;
         card.footnote = Backend.translate(pile);
         handcardAreaItem.add(card);
@@ -104,17 +104,17 @@ RowLayout {
   }
 
   function retractPile(pile) {
-    let expanded_pile_names = Object.keys(expanded_piles);
+    const expanded_pile_names = Object.keys(expanded_piles);
     if (expanded_pile_names.indexOf(pile) === -1)
       return;
 
-    let parentPos = roomScene.mapFromItem(self, 0, 0);
+    const parentPos = roomScene.mapFromItem(self, 0, 0);
 
     delete expanded_piles[pile];
     if (pile === "_equip") {
-      let equips = self.equipArea.getAllCards();
+      const equips = self.equipArea.getAllCards();
       equips.forEach(data => {
-        let card = handcardAreaItem.remove([data.cid])[0];
+        const card = handcardAreaItem.remove([data.cid])[0];
         card.origX = parentPos.x;
         card.origY = parentPos.y;
         card.destroyOnStop();
@@ -122,9 +122,9 @@ RowLayout {
       })
       handcardAreaItem.updateCardPosition();
     } else {
-      let ids = JSON.parse(Backend.callLuaFunction("GetPile", [self.playerid, pile]));
+      const ids = JSON.parse(Backend.callLuaFunction("GetPile", [self.playerid, pile]));
       ids.forEach(id => {
-        let card = handcardAreaItem.remove([id])[0];
+        const card = handcardAreaItem.remove([id])[0];
         card.origX = parentPos.x;
         card.origY = parentPos.y;
         card.destroyOnStop();
@@ -159,7 +159,8 @@ RowLayout {
       return ret;
     }
     if (cname) {
-      let ids = [], cards = handcardAreaItem.cards;
+      const ids = [];
+      let cards = handcardAreaItem.cards;
       for (let i = 0; i < cards.length; i++) {
         if (cardValid(cards[i].cid, cname)) {
           ids.push(cards[i].cid);
@@ -177,7 +178,7 @@ RowLayout {
 
       // Must manually analyze pattern here
       let pile_list = cname.split("|")[4];
-      let pile_data = JSON.parse(Backend.callLuaFunction("GetAllPiles", [self.playerid]));
+      const pile_data = JSON.parse(Backend.callLuaFunction("GetAllPiles", [self.playerid]));
       if (pile_list && pile_list !== "." && !(pile_data instanceof Array)) {
         pile_list = pile_list.split(",");
         for (let pile_name of pile_list) {
@@ -196,15 +197,15 @@ RowLayout {
       return;
     }
 
-    let ids = [], cards = handcardAreaItem.cards;
+    const ids = [], cards = handcardAreaItem.cards;
     for (let i = 0; i < cards.length; i++) {
       if (JSON.parse(Backend.callLuaFunction("CanUseCard", [cards[i].cid, Self.id]))) {
         ids.push(cards[i].cid);
       } else {
         // cannot use? considering special_skills
-        let skills = JSON.parse(Backend.callLuaFunction("GetCardSpecialSkills", [cards[i].cid]));
+        const skills = JSON.parse(Backend.callLuaFunction("GetCardSpecialSkills", [cards[i].cid]));
         for (let j = 0; j < skills.length; j++) {
-          let s = skills[j];
+          const s = skills[j];
           if (JSON.parse(Backend.callLuaFunction("ActiveCanUse", [s]))) {
             ids.push(cards[i].cid);
             break;
@@ -253,8 +254,8 @@ RowLayout {
   function updatePending() {
     if (pending_skill === "") return;
 
-    let enabled_cards = [];
-    let targets = roomScene.selected_targets;
+    const enabled_cards = [];
+    const targets = roomScene.selected_targets;
 
     handcardAreaItem.cards.forEach((card) => {
       if (card.selected || JSON.parse(Backend.callLuaFunction(
@@ -264,7 +265,7 @@ RowLayout {
         enabled_cards.push(card.cid);
     });
 
-    let cards = self.equipArea.getAllCards();
+    const cards = self.equipArea.getAllCards();
     cards.forEach(c => {
       if (JSON.parse(Backend.callLuaFunction(
         "ActiveCardFilter",
@@ -277,8 +278,8 @@ RowLayout {
       }
     })
 
-    let pile = Backend.callLuaFunction("GetExpandPileOfSkill", [pending_skill]);
-    let pile_ids = JSON.parse(Backend.callLuaFunction("GetPile", [self.playerid, pile]));
+    const pile = Backend.callLuaFunction("GetExpandPileOfSkill", [pending_skill]);
+    const pile_ids = JSON.parse(Backend.callLuaFunction("GetPile", [self.playerid, pile]));
     pile_ids.forEach(cid => {
       if (JSON.parse(Backend.callLuaFunction(
         "ActiveCardFilter",
@@ -313,7 +314,7 @@ RowLayout {
     pendings = [];
     handcardAreaItem.unselectAll();
     for (let i = 0; i < skillButtons.count; i++) {
-      let item = skillButtons.itemAt(i);
+      const item = skillButtons.itemAt(i);
       item.enabled = item.pressed;
     }
 
@@ -347,9 +348,9 @@ RowLayout {
   }
 
   function prelightSkill(skill_name, prelight) {
-    let btns = skillPanel.prelight_buttons;
+    const btns = skillPanel.prelight_buttons;
     for (let i = 0; i < btns.count; i++) {
-      let btn = btns.itemAt(i);
+      const btn = btns.itemAt(i);
       if (btn.orig === skill_name) {
         btn.prelighted = prelight;
         btn.enabled = true;
@@ -361,15 +362,15 @@ RowLayout {
     if (cname) {
       // if cname is presented, we are responding use or play.
       for (let i = 0; i < skillButtons.count; i++) {
-        let item = skillButtons.itemAt(i);
-        let fitpattern = JSON.parse(Backend.callLuaFunction("SkillFitPattern", [item.orig, cname]));
-        let canresp = JSON.parse(Backend.callLuaFunction("SkillCanResponse", [item.orig, cardResponsing]));
+        const item = skillButtons.itemAt(i);
+        const fitpattern = JSON.parse(Backend.callLuaFunction("SkillFitPattern", [item.orig, cname]));
+        const canresp = JSON.parse(Backend.callLuaFunction("SkillCanResponse", [item.orig, cardResponsing]));
         item.enabled = fitpattern && canresp;
       }
       return;
     }
     for (let i = 0; i < skillButtons.count; i++) {
-      let item = skillButtons.itemAt(i);
+      const item = skillButtons.itemAt(i);
       item.enabled = JSON.parse(Backend.callLuaFunction("ActiveCanUse", [item.orig]));
     }
   }
@@ -387,8 +388,8 @@ RowLayout {
     unSelectAll();
     disableSkills();
 
-    let cards = handcardAreaItem.cards;
-    let toRemove = [];
+    const cards = handcardAreaItem.cards;
+    const toRemove = [];
     for (let c of cards) {
       toRemove.push(c.cid);
       c.origY += 30;
@@ -400,7 +401,7 @@ RowLayout {
 
     skillPanel.clearSkills();
 
-    let skills = JSON.parse(Backend.callLuaFunction("GetPlayerSkills", [Self.id]));
+    const skills = JSON.parse(Backend.callLuaFunction("GetPlayerSkills", [Self.id]));
     for (let s of skills) {
       addSkill(s.name);
     }
diff --git a/Fk/RoomElement/GeneralCardItem.qml b/Fk/RoomElement/GeneralCardItem.qml
index e0e6a015..7ed4535b 100644
--- a/Fk/RoomElement/GeneralCardItem.qml
+++ b/Fk/RoomElement/GeneralCardItem.qml
@@ -155,14 +155,14 @@ CardItem {
   }
 
   onNameChanged: {
-    let data = JSON.parse(Backend.callLuaFunction("GetGeneralData", [name]));
+    const data = JSON.parse(Backend.callLuaFunction("GetGeneralData", [name]));
     kingdom = data.kingdom;
     subkingdom = (data.subkingdom !== kingdom && data.subkingdom) || "";
     hp = data.hp;
     maxHp = data.maxHp;
     shieldNum = data.shield;
 
-    let splited = name.split("__");
+    const splited = name.split("__");
     if (splited.length > 1) {
       pkgName = splited[0];
     } else {
diff --git a/Fk/RoomElement/GuanxingBox.qml b/Fk/RoomElement/GuanxingBox.qml
index cb57bfd2..ba1c870e 100644
--- a/Fk/RoomElement/GuanxingBox.qml
+++ b/Fk/RoomElement/GuanxingBox.qml
@@ -144,9 +144,9 @@ GraphicsBox {
   }
 
   function getResult() {
-    let ret = [];
+    const ret = [];
     result.forEach(t => {
-      let t2 = [];
+      const t2 = [];
       t.forEach(v => t2.push(v.cid));
       ret.push(t2);
     });
diff --git a/Fk/RoomElement/HandcardArea.qml b/Fk/RoomElement/HandcardArea.qml
index 779fa5e5..c9c20228 100644
--- a/Fk/RoomElement/HandcardArea.qml
+++ b/Fk/RoomElement/HandcardArea.qml
@@ -40,7 +40,7 @@ Item {
 
   function remove(outputs)
   {
-    let result = cardArea.remove(outputs);
+    const result = cardArea.remove(outputs);
     let card;
     for (let i = 0; i < result.length; i++) {
       card = result[i];
@@ -87,7 +87,7 @@ Item {
     area.updateCardPosition(true);
 
     for (let i = 0; i < cards.length; i++) {
-      let card = cards[i];
+      const card = cards[i];
       if (card.selected) {
         if (!selectedCards.contains(card))
           selectCard(card);
diff --git a/Fk/RoomElement/InvisibleCardArea.qml b/Fk/RoomElement/InvisibleCardArea.qml
index 2a01aa28..14e0a570 100644
--- a/Fk/RoomElement/InvisibleCardArea.qml
+++ b/Fk/RoomElement/InvisibleCardArea.qml
@@ -50,16 +50,16 @@ Item {
 
   function remove(outputs)
   {
-    let component = Qt.createComponent("CardItem.qml");
+    const component = Qt.createComponent("CardItem.qml");
     if (component.status !== Component.Ready)
       return [];
 
-    let parentPos = roomScene.mapFromItem(root, 0, 0);
+    const parentPos = roomScene.mapFromItem(root, 0, 0);
     let card;
-    let items = [];
+    const items = [];
     for (let i = 0; i < outputs.length; i++) {
       if (_contains(outputs[i])) {
-        let state = JSON.parse(Backend.callLuaFunction("GetCardData", [outputs[i]]))
+        const state = JSON.parse(Backend.callLuaFunction("GetCardData", [outputs[i]]))
         state.x = parentPos.x;
         state.y = parentPos.y;
         state.opacity = 0;
@@ -90,7 +90,7 @@ Item {
     let i, card;
 
     if (animated) {
-      let parentPos = roomScene.mapFromItem(root, 0, 0);
+      const parentPos = roomScene.mapFromItem(root, 0, 0);
       for (i = 0; i < pendingInput.length; i++) {
         card = pendingInput[i];
         card.origX = parentPos.x - card.width / 2 + ((i - pendingInput.length / 2) * 15);
diff --git a/Fk/RoomElement/MiscStatus.qml b/Fk/RoomElement/MiscStatus.qml
index 4d924635..f056ce95 100644
--- a/Fk/RoomElement/MiscStatus.qml
+++ b/Fk/RoomElement/MiscStatus.qml
@@ -9,9 +9,9 @@ Item {
   visible: roundNum || pileNum
 
   function getTimeString(time) {
-    let s = time % 60;
-    let m = (time - s) / 60;
-    let h = (time - s - m * 60) / 3600;
+    const s = time % 60;
+    const m = (time - s) / 60;
+    const h = (time - s - m * 60) / 3600;
     return h ? `${h}:${m}:${s}` : `${m}:${s}`;
   }
 
diff --git a/Fk/RoomElement/Photo.qml b/Fk/RoomElement/Photo.qml
index a3c434e6..318701bd 100644
--- a/Fk/RoomElement/Photo.qml
+++ b/Fk/RoomElement/Photo.qml
@@ -293,7 +293,7 @@ Item {
     }
 
     function updatePileInfo(areaName) {
-      let data = JSON.parse(Backend.callLuaFunction("GetPile", [root.playerid, areaName]));
+      const data = JSON.parse(Backend.callLuaFunction("GetPile", [root.playerid, areaName]));
       if (data.length === 0) {
         root.markArea.removeMark(areaName);
       } else {
@@ -576,7 +576,7 @@ Item {
 
   onGeneralChanged: {
     if (!roomScene.isStarted) return;
-    let text = Backend.translate(general);
+    const text = Backend.translate(general);
     if (text.length > 6) {
       generalName.text = "";
       longGeneralName.text = text;
diff --git a/Fk/RoomElement/SkillArea.qml b/Fk/RoomElement/SkillArea.qml
index 0dc30885..997ee5a7 100644
--- a/Fk/RoomElement/SkillArea.qml
+++ b/Fk/RoomElement/SkillArea.qml
@@ -111,7 +111,7 @@ Flickable {
       return false;
     };
 
-    let data = JSON.parse(Backend.callLuaFunction(
+    const data = JSON.parse(Backend.callLuaFunction(
       "GetSkillData",
       [skill_name]
     ));
@@ -133,7 +133,7 @@ Flickable {
   function loseSkill(skill_name, prelight) {
     if (prelight) {
       for (let i = 0; i < prelight_skills.count; i++) {
-        let item = prelight_skills.get(i);
+        const item = prelight_skills.get(i);
         if (item.orig_skill == skill_name) {
           prelight_skills.remove(i);
         }
@@ -142,13 +142,13 @@ Flickable {
     }
 
     for (let i = 0; i < active_skills.count; i++) {
-      let item = active_skills.get(i);
+      const item = active_skills.get(i);
       if (item.orig_skill == skill_name) {
         active_skills.remove(i);
       }
     }
     for (let i = 0; i < not_active_skills.count; i++) {
-      let item = not_active_skills.get(i);
+      const item = not_active_skills.get(i);
       if (item.orig_skill == skill_name) {
         not_active_skills.remove(i);
       }
diff --git a/Fk/RoomElement/TablePile.qml b/Fk/RoomElement/TablePile.qml
index c67b8e06..f7f50e2e 100644
--- a/Fk/RoomElement/TablePile.qml
+++ b/Fk/RoomElement/TablePile.qml
@@ -61,7 +61,7 @@ Item {
     area.add(inputs);
     // if (!inputs instanceof Array)
     for (let i = 0; i < inputs.length; i++) {
-      let c = inputs[i];
+      const c = inputs[i];
       c.footnoteVisible = true;
       c.selectable = true;
       c.height = c.height * 0.8;
@@ -76,14 +76,14 @@ Item {
 
     let result = area.remove(outputs);
     for (let i = 0; i < result.length; i++) {
-      let c = result[i];
+      const c = result[i];
       c.footnoteVisible = false;
       c.selectable = false;
       c.height = c.height / 0.8;
       c.width = c.width / 0.8;
       c.rotation = 0;
     }
-    let vanished = [];
+    const vanished = [];
     if (result.length < outputs.length) {
       for (i = 0; i < outputs.length; i++) {
         let exists = false;
@@ -131,8 +131,8 @@ Item {
 
     if (overflow) {
       //@to-do: Adjust cards in multiple lines if there are too many cards
-      let xLimit = root.width - card.width;
-      let spacing = xLimit / (cards.length - 1);
+      const xLimit = root.width - card.width;
+      const spacing = xLimit / (cards.length - 1);
       for (i = 0; i < cards.length; i++) {
         card = cards[i];
         card.origX = i * spacing;
@@ -140,8 +140,8 @@ Item {
       }
     }
 
-    let offsetX = Math.max(0, (root.width - cards.length * card.width) / 2);
-    let parentPos = roomScene.mapFromItem(root, 0, 0);
+    const offsetX = Math.max(0, (root.width - cards.length * card.width) / 2);
+    const parentPos = roomScene.mapFromItem(root, 0, 0);
     for (i = 0; i < cards.length; i++) {
       card = cards[i];
       card.origX += parentPos.x + offsetX;
diff --git a/Fk/SkillInteraction/SkillCombo.qml b/Fk/SkillInteraction/SkillCombo.qml
index 178595c6..e976fb20 100644
--- a/Fk/SkillInteraction/SkillCombo.qml
+++ b/Fk/SkillInteraction/SkillCombo.qml
@@ -35,7 +35,7 @@ MetroButton {
 
   onClicked: {
     roomScene.popupBox.sourceComponent = Qt.createComponent("../RoomElement/ChoiceBox.qml");
-    let box = roomScene.popupBox.item;
+    const box = roomScene.popupBox.item;
     box.options = choices;
     box.accepted.connect(() => {
       answer = choices[box.result];
diff --git a/Fk/main.qml b/Fk/main.qml
index a964169a..fbc2b78d 100644
--- a/Fk/main.qml
+++ b/Fk/main.qml
@@ -168,7 +168,7 @@ Window {
     }
 
     function fetchMessage() {
-      let ret = pending_message.splice(0, 1)[0];
+      const ret = pending_message.splice(0, 1)[0];
       if (pending_message.length === 0) {
         is_pending = false;
       }
@@ -176,7 +176,7 @@ Window {
     }
 
     function handleMessage(command, jsonData) {
-      let cb = callbacks[command]
+      const cb = callbacks[command]
       if (typeof(cb) === "function") {
         cb(jsonData);
       } else {
diff --git a/Fk/skin-bank.js b/Fk/skin-bank.js
index f1c7c875..f40169cb 100644
--- a/Fk/skin-bank.js
+++ b/Fk/skin-bank.js
@@ -20,9 +20,9 @@ var TILE_ICON_DIR = AppPath + "/image/button/tileicon/"
 var LOBBY_IMG_DIR = AppPath + "/image/lobby/";
 
 function getGeneralPicture(name) {
-  let data = JSON.parse(Backend.callLuaFunction("GetGeneralData", [name]));
-  let extension = data.extension;
-  let path = AppPath + "/packages/" + extension + "/image/generals/" + name + ".jpg";
+  const data = JSON.parse(Backend.callLuaFunction("GetGeneralData", [name]));
+  const extension = data.extension;
+  const path = AppPath + "/packages/" + extension + "/image/generals/" + name + ".jpg";
   if (Backend.exists(path)) {
     return path;
   }
@@ -54,7 +54,7 @@ function getCardPicture(cidOrName) {
 }
 
 function getDelayedTrickPicture(name) {
-  let extension = Backend.callLuaFunction("GetCardExtensionByName", [name]);
+  const extension = Backend.callLuaFunction("GetCardExtensionByName", [name]);
 
   let path = AppPath + "/packages/" + extension + "/image/card/delayedTrick/" + name + ".png";
   if (Backend.exists(path)) {
@@ -70,9 +70,9 @@ function getDelayedTrickPicture(name) {
 
 
 function getEquipIcon(cid, icon) {
-  let data = JSON.parse(Backend.callLuaFunction("GetCardData", [cid]));
-  let extension = data.extension;
-  let name = icon || data.name;
+  const data = JSON.parse(Backend.callLuaFunction("GetCardData", [cid]));
+  const extension = data.extension;
+  const name = icon || data.name;
   let path = AppPath + "/packages/" + extension + "/image/card/equipIcon/" + name + ".png";
   if (Backend.exists(path)) {
     return path;
diff --git a/lua/server/room.lua b/lua/server/room.lua
index 71bab027..0978ed36 100644
--- a/lua/server/room.lua
+++ b/lua/server/room.lua
@@ -1307,8 +1307,8 @@ function Room:askForGuanxing(player, cards, top_limit, bottom_limit, customNotif
       bottom = d[2]
     end
   else
-    top = table.random(cards, top_limit and top_limit[2] or #cards)
-    bottom = table.shuffle(table.filter(cards, function(id) return not table.contains(top, id) end))
+    top = table.random(cards, top_limit and top_limit[2] or #cards) or {}
+    bottom = table.shuffle(table.filter(cards, function(id) return not table.contains(top, id) end)) or {}
   end
 
   if not noPut then