From 0362d3b05db2e22e1e1759fe1c00693f013b2131 Mon Sep 17 00:00:00 2001
From: John McLear <john@mclear.co.uk>
Date: Sun, 20 Dec 2020 07:15:58 +0000
Subject: [PATCH] lint: pad prefix files (#4577)

* lint: pad_connectionstatus

* lint: pad_utils

* lint: pad_userlist.js -- still WIP

* shift underscore not to be in require but to be used from window

* lint: pad_modals

* pad_impexp.js

* lint: more errors done

* lint: auto reconn

* lint: pad_editor

* lint: finish auto reconn

* lint: imp exp rework

* lint: import

* lint: pad.js nearly done but pizza here...

* lint: clientVars global query

* put clientVars in window

* Revert incorrect lint fixes

* Properly fix guard-for-in lint errors

* Properly fix no-unused-vars error regarding `gritter`

* Refine lint fixes

Co-authored-by: Richard Hansen <rhansen@rhansen.org>
---
 src/static/js/pad.js                     | 480 ++++++++++++-----------
 src/static/js/pad_automatic_reconnect.js |  50 +--
 src/static/js/pad_connectionstatus.js    |  24 +-
 src/static/js/pad_cookie.js              |   2 +
 src/static/js/pad_editbar.js             |   1 +
 src/static/js/pad_editor.js              |  47 +--
 src/static/js/pad_impexp.js              |  84 ++--
 src/static/js/pad_modals.js              |  14 +-
 src/static/js/pad_savedrevs.js           |  11 +-
 src/static/js/pad_userlist.js            | 254 ++++++------
 src/static/js/pad_utils.js               |   4 +-
 11 files changed, 512 insertions(+), 459 deletions(-)

diff --git a/src/static/js/pad.js b/src/static/js/pad.js
index 424c45241..c19bd58ea 100644
--- a/src/static/js/pad.js
+++ b/src/static/js/pad.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
@@ -20,8 +22,6 @@
  * limitations under the License.
  */
 
-/* global $, window */
-
 let socket;
 
 // These jQuery things should create local references, but for now `require()`
@@ -43,24 +43,13 @@ const padsavedrevs = require('./pad_savedrevs');
 const paduserlist = require('./pad_userlist').paduserlist;
 const padutils = require('./pad_utils').padutils;
 const colorutils = require('./colorutils').colorutils;
-var randomString = require('./pad_utils').randomString;
-const gritter = require('./gritter').gritter;
+const randomString = require('./pad_utils').randomString;
+require('./gritter'); // Mutates the jQuery object to make $.gritter available.
 
 const hooks = require('./pluginfw/hooks');
 
 let receivedClientVars = false;
 
-function randomString() {
-  const chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
-  const string_length = 20;
-  let randomstring = '';
-  for (let i = 0; i < string_length; i++) {
-    const rnum = Math.floor(Math.random() * chars.length);
-    randomstring += chars.substring(rnum, rnum + 1);
-  }
-  return `t.${randomstring}`;
-}
-
 // This array represents all GET-parameters which can be used to change a setting.
 //   name:     the parameter-name, eg  `?noColors=true`  =>  `noColors`
 //   checkVal: the callback is only executed when
@@ -68,26 +57,101 @@ function randomString() {
 //                * the parameter was supplied and checkVal is null
 //   callback: the function to call when all above succeeds, `val` is the value supplied by the user
 const getParameters = [
-  {name: 'noColors', checkVal: 'true', callback(val) { settings.noColors = true; $('#clearAuthorship').hide(); }},
-  {name: 'showControls', checkVal: 'true', callback(val) { $('#editbar').css('display', 'flex'); }},
-  {name: 'showChat', checkVal: null, callback(val) { if (val === 'false') { settings.hideChat = true; chat.hide(); $('#chaticon').hide(); } }},
-  {name: 'showLineNumbers', checkVal: 'false', callback(val) { settings.LineNumbersDisabled = true; }},
-  {name: 'useMonospaceFont', checkVal: 'true', callback(val) { settings.useMonospaceFontGlobal = true; }},
-  // If the username is set as a parameter we should set a global value that we can call once we have initiated the pad.
-  {name: 'userName', checkVal: null, callback(val) { settings.globalUserName = decodeURIComponent(val); clientVars.userName = decodeURIComponent(val); }},
-  // If the userColor is set as a parameter, set a global value to use once we have initiated the pad.
-  {name: 'userColor', checkVal: null, callback(val) { settings.globalUserColor = decodeURIComponent(val); clientVars.userColor = decodeURIComponent(val); }},
-  {name: 'rtl', checkVal: 'true', callback(val) { settings.rtlIsTrue = true; }},
-  {name: 'alwaysShowChat', checkVal: 'true', callback(val) { if (!settings.hideChat) chat.stickToScreen(); }},
-  {name: 'chatAndUsers', checkVal: 'true', callback(val) { chat.chatAndUsers(); }},
-  {name: 'lang', checkVal: null, callback(val) { window.html10n.localize([val, 'en']); Cookies.set('language', val); }},
+  {
+    name: 'noColors',
+    checkVal: 'true',
+    callback: (val) => {
+      settings.noColors = true;
+      $('#clearAuthorship').hide();
+    },
+  },
+  {
+    name: 'showControls',
+    checkVal: 'true',
+    callback: (val) => {
+      $('#editbar').css('display', 'flex');
+    },
+  },
+  {
+    name: 'showChat',
+    checkVal: null,
+    callback: (val) => {
+      if (val === 'false') {
+        settings.hideChat = true;
+        chat.hide();
+        $('#chaticon').hide();
+      }
+    },
+  },
+  {
+    name: 'showLineNumbers',
+    checkVal: 'false',
+    callback: (val) => {
+      settings.LineNumbersDisabled = true;
+    },
+  },
+  {
+    name: 'useMonospaceFont',
+    checkVal: 'true',
+    callback: (val) => {
+      settings.useMonospaceFontGlobal = true;
+    },
+  },
+  // If the username is set as a parameter we should set a global value that we can call once we
+  // have initiated the pad.
+  {
+    name: 'userName',
+    checkVal: null,
+    callback: (val) => {
+      settings.globalUserName = decodeURIComponent(val);
+      clientVars.userName = decodeURIComponent(val);
+    },
+  },
+  // If the userColor is set as a parameter, set a global value to use once we have initiated the
+  // pad.
+  {
+    name: 'userColor',
+    checkVal: null,
+    callback: (val) => {
+      settings.globalUserColor = decodeURIComponent(val);
+      clientVars.userColor = decodeURIComponent(val);
+    },
+  },
+  {
+    name: 'rtl',
+    checkVal: 'true',
+    callback: (val) => {
+      settings.rtlIsTrue = true;
+    },
+  },
+  {
+    name: 'alwaysShowChat',
+    checkVal: 'true',
+    callback: (val) => {
+      if (!settings.hideChat) chat.stickToScreen();
+    },
+  },
+  {
+    name: 'chatAndUsers',
+    checkVal: 'true',
+    callback: (val) => {
+      chat.chatAndUsers();
+    },
+  },
+  {
+    name: 'lang',
+    checkVal: null,
+    callback: (val) => {
+      window.html10n.localize([val, 'en']);
+      Cookies.set('language', val);
+    },
+  },
 ];
 
-function getParams() {
+const getParams = () => {
   // Tries server enforced options first..
-  for (var i = 0; i < getParameters.length; i++) {
-    var setting = getParameters[i];
-    var value = clientVars.padOptions[setting.name];
+  for (const setting of getParameters) {
+    const value = clientVars.padOptions[setting.name];
     if (value.toString() === setting.checkVal) {
       setting.callback(value);
     }
@@ -96,19 +160,18 @@ function getParams() {
   // Then URL applied stuff
   const params = getUrlVars();
 
-  for (var i = 0; i < getParameters.length; i++) {
-    var setting = getParameters[i];
-    var value = params[setting.name];
+  for (const setting of getParameters) {
+    const value = params[setting.name];
 
-    if (value && (value == setting.checkVal || setting.checkVal == null)) {
+    if (value && (value === setting.checkVal || setting.checkVal == null)) {
       setting.callback(value);
     }
   }
-}
+};
 
-function getUrlVars() {
-  const vars = []; let
-    hash;
+const getUrlVars = () => {
+  const vars = [];
+  let hash;
   const hashes = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&');
   for (let i = 0; i < hashes.length; i++) {
     hash = hashes[i].split('=');
@@ -116,12 +179,13 @@ function getUrlVars() {
     vars[hash[0]] = hash[1];
   }
   return vars;
-}
+};
 
-function sendClientReady(isReconnect, messageType) {
+const sendClientReady = (isReconnect, messageType) => {
   messageType = typeof messageType !== 'undefined' ? messageType : 'CLIENT_READY';
   let padId = document.location.pathname.substring(document.location.pathname.lastIndexOf('/') + 1);
-  padId = decodeURIComponent(padId); // unescape neccesary due to Safari and Opera interpretation of spaces
+  // unescape neccesary due to Safari and Opera interpretation of spaces
+  padId = decodeURIComponent(padId);
 
   if (!isReconnect) {
     const titleArray = document.title.split('|');
@@ -151,12 +215,12 @@ function sendClientReady(isReconnect, messageType) {
   }
 
   socket.json.send(msg);
-}
+};
 
-function handshake() {
+const handshake = () => {
   const loc = document.location;
   // get the correct port
-  const port = loc.port == '' ? (loc.protocol == 'https:' ? 443 : 80) : loc.port;
+  const port = loc.port === '' ? (loc.protocol === 'https:' ? 443 : 80) : loc.port;
   // create the url
   const url = `${loc.protocol}//${loc.hostname}:${port}/`;
   // find out in which subfolder we are
@@ -211,12 +275,10 @@ function handshake() {
     throw new Error(`socket.io connection error: ${JSON.stringify(error)}`);
   });
 
-  let initalized = false;
-
   socket.on('message', (obj) => {
     // the access was not granted, give the user a message
     if (obj.accessStatus) {
-      if (obj.accessStatus == 'deny') {
+      if (obj.accessStatus === 'deny') {
         $('#loading').hide();
         $('#permissionDenied').show();
 
@@ -226,18 +288,15 @@ function handshake() {
           $('#editorloadingbox').show();
         }
       }
-    }
-
-    // if we haven't recieved the clientVars yet, then this message should it be
-    else if (!receivedClientVars && obj.type == 'CLIENT_VARS') {
+    } else if (!receivedClientVars && obj.type === 'CLIENT_VARS') {
+      // if we haven't recieved the clientVars yet, then this message should it be
       receivedClientVars = true;
 
       // set some client vars
-      clientVars = obj.data;
+      window.clientVars = obj.data;
 
       // initalize the pad
       pad._afterHandshake();
-      initalized = true;
 
       if (clientVars.readonly) {
         chat.hide();
@@ -255,63 +314,61 @@ function handshake() {
       });
 
       // If the LineNumbersDisabled value is set to true then we need to hide the Line Numbers
-      if (settings.LineNumbersDisabled == true) {
+      if (settings.LineNumbersDisabled === true) {
         pad.changeViewOption('showLineNumbers', false);
       }
 
-      // If the noColors value is set to true then we need to hide the background colors on the ace spans
-      if (settings.noColors == true) {
+      // If the noColors value is set to true then we need to
+      // hide the background colors on the ace spans
+      if (settings.noColors === true) {
         pad.changeViewOption('noColors', true);
       }
 
-      if (settings.rtlIsTrue == true) {
+      if (settings.rtlIsTrue === true) {
         pad.changeViewOption('rtlIsTrue', true);
       }
 
       // If the Monospacefont value is set to true then change it to monospace.
-      if (settings.useMonospaceFontGlobal == true) {
+      if (settings.useMonospaceFontGlobal === true) {
         pad.changeViewOption('padFontFamily', 'monospace');
       }
-      // if the globalUserName value is set we need to tell the server and the client about the new authorname
+      // if the globalUserName value is set we need to tell the server and
+      // the client about the new authorname
       if (settings.globalUserName !== false) {
         pad.notifyChangeName(settings.globalUserName); // Notifies the server
         pad.myUserInfo.name = settings.globalUserName;
         $('#myusernameedit').val(settings.globalUserName); // Updates the current users UI
       }
       if (settings.globalUserColor !== false && colorutils.isCssHex(settings.globalUserColor)) {
-        // Add a 'globalUserColor' property to myUserInfo, so collabClient knows we have a query parameter.
+        // Add a 'globalUserColor' property to myUserInfo,
+        // so collabClient knows we have a query parameter.
         pad.myUserInfo.globalUserColor = settings.globalUserColor;
         pad.notifyChangeColor(settings.globalUserColor); // Updates pad.myUserInfo.colorId
         paduserlist.setMyUserInfo(pad.myUserInfo);
       }
-    }
-    // This handles every Message after the clientVars
-    else {
-      // this message advices the client to disconnect
-      if (obj.disconnect) {
-        padconnectionstatus.disconnected(obj.disconnect);
-        socket.disconnect();
+    } else if (obj.disconnect) {
+      padconnectionstatus.disconnected(obj.disconnect);
+      socket.disconnect();
 
-        // block user from making any change to the pad
-        padeditor.disable();
-        padeditbar.disable();
-        padimpexp.disable();
+      // block user from making any change to the pad
+      padeditor.disable();
+      padeditbar.disable();
+      padimpexp.disable();
 
-        return;
-      } else {
-        pad.collabClient.handleMessageFromServer(obj);
-      }
+      return;
+    } else {
+      pad.collabClient.handleMessageFromServer(obj);
     }
   });
   // Bind the colorpicker
-  const fb = $('#colorpicker').farbtastic({callback: '#mycolorpickerpreview', width: 220});
+  $('#colorpicker').farbtastic({callback: '#mycolorpickerpreview', width: 220});
   // Bind the read only button
   $('#readonlyinput').on('click', () => {
     padeditbar.setEmbedLinks();
   });
-}
+};
 
-var pad = {
+const pad = {
   // don't access these directly from outside this file, except
   // for debugging
   collabClient: null,
@@ -322,44 +379,28 @@ var pad = {
   padOptions: {},
 
   // these don't require init; clientVars should all go through here
-  getPadId() {
-    return clientVars.padId;
-  },
-  getClientIp() {
-    return clientVars.clientIp;
-  },
-  getColorPalette() {
-    return clientVars.colorPalette;
-  },
-  getIsDebugEnabled() {
-    return clientVars.debugEnabled;
-  },
-  getPrivilege(name) {
-    return clientVars.accountPrivs[name];
-  },
-  getUserId() {
-    return pad.myUserInfo.userId;
-  },
-  getUserName() {
-    return pad.myUserInfo.name;
-  },
-  userList() {
-    return paduserlist.users();
-  },
-  switchToPad(padId) {
-    let newHref = new RegExp(/.*\/p\/[^\/]+/).exec(document.location.pathname) || clientVars.padId;
+  getPadId: () => clientVars.padId,
+  getClientIp: () => clientVars.clientIp,
+  getColorPalette: () => clientVars.colorPalette,
+  getIsDebugEnabled: () => clientVars.debugEnabled,
+  getPrivilege: (name) => clientVars.accountPrivs[name],
+  getUserId: () => pad.myUserInfo.userId,
+  getUserName: () => pad.myUserInfo.name,
+  userList: () => paduserlist.users(),
+  switchToPad: (padId) => {
+    let newHref = new RegExp(/.*\/p\/[^/]+/).exec(document.location.pathname) || clientVars.padId;
     newHref = newHref[0];
 
     const options = clientVars.padOptions;
     if (typeof options !== 'undefined' && options != null) {
-      var option_str = [];
+      const optionArr = [];
       $.each(options, (k, v) => {
         const str = `${k}=${v}`;
-        option_str.push(str);
+        optionArr.push(str);
       });
-      var option_str = option_str.join('&');
+      const optionStr = optionArr.join('&');
 
-      newHref = `${newHref}?${option_str}`;
+      newHref = `${newHref}?${optionStr}`;
     }
 
     // destroy old pad from DOM
@@ -373,21 +414,21 @@ var pad = {
       window.history.pushState('', '', newHref);
       receivedClientVars = false;
       sendClientReady(false, 'SWITCH_TO_PAD');
-    } else // fallback
-    {
+    } else {
+      // fallback
       window.location.href = newHref;
     }
   },
-  sendClientMessage(msg) {
+  sendClientMessage: (msg) => {
     pad.collabClient.sendClientMessage(msg);
   },
 
-  init() {
+  init: () => {
     padutils.setupGlobalExceptionHandler();
 
     $(document).ready(() => {
       // start the custom js
-      if (typeof customStart === 'function') customStart();
+      if (typeof customStart === 'function') customStart(); // eslint-disable-line no-undef
       handshake();
 
       // To use etherpad you have to allow cookies.
@@ -406,7 +447,6 @@ var pad = {
     pad.initTime = +(new Date());
     pad.padOptions = clientVars.initialOptions;
 
-    // order of inits is important here:
     pad.myUserInfo = {
       userId: clientVars.userId,
       name: clientVars.userName,
@@ -414,18 +454,60 @@ var pad = {
       colorId: clientVars.userColor,
     };
 
+    const postAceInit = () => {
+      padeditbar.init();
+      setTimeout(() => {
+        padeditor.ace.focus();
+      }, 0);
+      // if we have a cookie for always showing chat then show it
+      if (padcookie.getPref('chatAlwaysVisible')) {
+        chat.stickToScreen(true); // stick it to the screen
+        $('#options-stickychat').prop('checked', true); // set the checkbox to on
+      }
+      // if we have a cookie for always showing chat then show it
+      if (padcookie.getPref('chatAndUsers')) {
+        chat.chatAndUsers(true); // stick it to the screen
+        $('#options-chatandusers').prop('checked', true); // set the checkbox to on
+      }
+      if (padcookie.getPref('showAuthorshipColors') === false) {
+        pad.changeViewOption('showAuthorColors', false);
+      }
+      if (padcookie.getPref('showLineNumbers') === false) {
+        pad.changeViewOption('showLineNumbers', false);
+      }
+      if (padcookie.getPref('rtlIsTrue') === true) {
+        pad.changeViewOption('rtlIsTrue', true);
+      }
+      pad.changeViewOption('padFontFamily', padcookie.getPref('padFontFamily'));
+      $('#viewfontmenu').val(padcookie.getPref('padFontFamily')).niceSelect('update');
+
+      // Prevent sticky chat or chat and users to be checked for mobiles
+      const checkChatAndUsersVisibility = (x) => {
+        if (x.matches) { // If media query matches
+          $('#options-chatandusers:checked').click();
+          $('#options-stickychat:checked').click();
+        }
+      };
+      const mobileMatch = window.matchMedia('(max-width: 800px)');
+      mobileMatch.addListener(checkChatAndUsersVisibility); // check if window resized
+      setTimeout(() => { checkChatAndUsersVisibility(mobileMatch); }, 0); // check now after load
+
+      $('#editorcontainer').addClass('initialized');
+
+      hooks.aCallAll('postAceInit', {ace: padeditor.ace, pad});
+    };
+
+    // order of inits is important here:
     padimpexp.init(this);
     padsavedrevs.init(this);
-
     padeditor.init(postAceInit, pad.padOptions.view || {}, this);
-
     paduserlist.init(pad.myUserInfo, this);
     padconnectionstatus.init();
     padmodals.init(this);
 
-    pad.collabClient = getCollabClient(padeditor.ace, clientVars.collab_client_vars, pad.myUserInfo, {
-      colorPalette: pad.getColorPalette(),
-    }, pad);
+    pad.collabClient = getCollabClient(
+        padeditor.ace, clientVars.collab_client_vars, pad.myUserInfo,
+        {colorPalette: pad.getColorPalette()}, pad);
     pad.collabClient.setOnUserJoin(pad.handleUserJoin);
     pad.collabClient.setOnUpdateUserInfo(pad.handleUserUpdate);
     pad.collabClient.setOnUserLeave(pad.handleUserLeave);
@@ -434,68 +516,27 @@ var pad = {
     pad.collabClient.setOnInternalAction(pad.handleCollabAction);
 
     // load initial chat-messages
-    if (clientVars.chatHead != -1) {
+    if (clientVars.chatHead !== -1) {
       const chatHead = clientVars.chatHead;
       const start = Math.max(chatHead - 100, 0);
       pad.collabClient.sendMessage({type: 'GET_CHAT_MESSAGES', start, end: chatHead});
-    } else // there are no messages
-    {
+    } else {
+      // there are no messages
       $('#chatloadmessagesbutton').css('display', 'none');
     }
-
-    function postAceInit() {
-      padeditbar.init();
-      setTimeout(() => {
-        padeditor.ace.focus();
-      }, 0);
-      if (padcookie.getPref('chatAlwaysVisible')) { // if we have a cookie for always showing chat then show it
-        chat.stickToScreen(true); // stick it to the screen
-        $('#options-stickychat').prop('checked', true); // set the checkbox to on
-      }
-      if (padcookie.getPref('chatAndUsers')) { // if we have a cookie for always showing chat then show it
-        chat.chatAndUsers(true); // stick it to the screen
-        $('#options-chatandusers').prop('checked', true); // set the checkbox to on
-      }
-      if (padcookie.getPref('showAuthorshipColors') == false) {
-        pad.changeViewOption('showAuthorColors', false);
-      }
-      if (padcookie.getPref('showLineNumbers') == false) {
-        pad.changeViewOption('showLineNumbers', false);
-      }
-      if (padcookie.getPref('rtlIsTrue') == true) {
-        pad.changeViewOption('rtlIsTrue', true);
-      }
-      pad.changeViewOption('padFontFamily', padcookie.getPref('padFontFamily'));
-      $('#viewfontmenu').val(padcookie.getPref('padFontFamily')).niceSelect('update');
-
-      // Prevent sticky chat or chat and users to be checked for mobiles
-      function checkChatAndUsersVisibility(x) {
-        if (x.matches) { // If media query matches
-          $('#options-chatandusers:checked').click();
-          $('#options-stickychat:checked').click();
-        }
-      }
-      const mobileMatch = window.matchMedia('(max-width: 800px)');
-      mobileMatch.addListener(checkChatAndUsersVisibility); // check if window resized
-      setTimeout(() => { checkChatAndUsersVisibility(mobileMatch); }, 0); // check now after load
-
-      $('#editorcontainer').addClass('initialized');
-
-      hooks.aCallAll('postAceInit', {ace: padeditor.ace, pad});
-    }
   },
-  dispose() {
+  dispose: () => {
     padeditor.dispose();
   },
-  notifyChangeName(newName) {
+  notifyChangeName: (newName) => {
     pad.myUserInfo.name = newName;
     pad.collabClient.updateUserInfo(pad.myUserInfo);
   },
-  notifyChangeColor(newColorId) {
+  notifyChangeColor: (newColorId) => {
     pad.myUserInfo.colorId = newColorId;
     pad.collabClient.updateUserInfo(pad.myUserInfo);
   },
-  changePadOption(key, value) {
+  changePadOption: (key, value) => {
     const options = {};
     options[key] = value;
     pad.handleOptionsChange(options);
@@ -506,32 +547,30 @@ var pad = {
           changedBy: pad.myUserInfo.name || 'unnamed',
         });
   },
-  changeViewOption(key, value) {
+  changeViewOption: (key, value) => {
     const options = {
       view: {},
     };
     options.view[key] = value;
     pad.handleOptionsChange(options);
   },
-  handleOptionsChange(opts) {
+  handleOptionsChange: (opts) => {
     // opts object is a full set of options or just
     // some options to change
     if (opts.view) {
       if (!pad.padOptions.view) {
         pad.padOptions.view = {};
       }
-      for (const k in opts.view) {
-        pad.padOptions.view[k] = opts.view[k];
-        padcookie.setPref(k, opts.view[k]);
+      for (const [k, v] of Object.entries(opts.view)) {
+        pad.padOptions.view[k] = v;
+        padcookie.setPref(k, v);
       }
       padeditor.setViewOptions(pad.padOptions.view);
     }
   },
-  getPadOptions() {
-    // caller shouldn't mutate the object
-    return pad.padOptions;
-  },
-  suggestUserName(userId, name) {
+  // caller shouldn't mutate the object
+  getPadOptions: () => pad.padOptions,
+  suggestUserName: (userId, name) => {
     pad.collabClient.sendClientMessage(
         {
           type: 'suggestUserName',
@@ -539,31 +578,31 @@ var pad = {
           newName: name,
         });
   },
-  handleUserJoin(userInfo) {
+  handleUserJoin: (userInfo) => {
     paduserlist.userJoinOrUpdate(userInfo);
   },
-  handleUserUpdate(userInfo) {
+  handleUserUpdate: (userInfo) => {
     paduserlist.userJoinOrUpdate(userInfo);
   },
-  handleUserLeave(userInfo) {
+  handleUserLeave: (userInfo) => {
     paduserlist.userLeave(userInfo);
   },
-  handleClientMessage(msg) {
-    if (msg.type == 'suggestUserName') {
-      if (msg.unnamedId == pad.myUserInfo.userId && msg.newName && !pad.myUserInfo.name) {
+  handleClientMessage: (msg) => {
+    if (msg.type === 'suggestUserName') {
+      if (msg.unnamedId === pad.myUserInfo.userId && msg.newName && !pad.myUserInfo.name) {
         pad.notifyChangeName(msg.newName);
         paduserlist.setMyUserInfo(pad.myUserInfo);
       }
-    } else if (msg.type == 'newRevisionList') {
+    } else if (msg.type === 'newRevisionList') {
       padsavedrevs.newRevisionList(msg.revisionList);
-    } else if (msg.type == 'revisionLabel') {
+    } else if (msg.type === 'revisionLabel') {
       padsavedrevs.newRevisionList(msg.revisionList);
-    } else if (msg.type == 'padoptions') {
+    } else if (msg.type === 'padoptions') {
       const opts = msg.options;
       pad.handleOptionsChange(opts);
     }
   },
-  dmesg(m) {
+  dmesg: (m) => {
     if (pad.getIsDebugEnabled()) {
       const djs = $('#djs').get(0);
       const wasAtBottom = (djs.scrollTop - (djs.scrollHeight - $(djs).height()) >= -20);
@@ -573,31 +612,30 @@ var pad = {
       }
     }
   },
-  handleChannelStateChange(newState, message) {
+  handleChannelStateChange: (newState, message) => {
     const oldFullyConnected = !!padconnectionstatus.isFullyConnected();
-    const wasConnecting = (padconnectionstatus.getStatus().what == 'connecting');
-    if (newState == 'CONNECTED') {
+    const wasConnecting = (padconnectionstatus.getStatus().what === 'connecting');
+    if (newState === 'CONNECTED') {
       padeditor.enable();
       padeditbar.enable();
       padimpexp.enable();
       padconnectionstatus.connected();
-    } else if (newState == 'RECONNECTING') {
+    } else if (newState === 'RECONNECTING') {
       padeditor.disable();
       padeditbar.disable();
       padimpexp.disable();
       padconnectionstatus.reconnecting();
-    } else if (newState == 'DISCONNECTED') {
+    } else if (newState === 'DISCONNECTED') {
       pad.diagnosticInfo.disconnectedMessage = message;
       pad.diagnosticInfo.padId = pad.getPadId();
       pad.diagnosticInfo.socket = {};
 
       // we filter non objects from the socket object and put them in the diagnosticInfo
       // this ensures we have no cyclic data - this allows us to stringify the data
-      for (const i in socket.socket) {
-        const value = socket.socket[i];
+      for (const [i, value] of Object.entries(socket.socket || {})) {
         const type = typeof value;
 
-        if (type == 'string' || type == 'number') {
+        if (type === 'string' || type === 'number') {
           pad.diagnosticInfo.socket[i] = value;
         }
       }
@@ -613,11 +651,11 @@ var pad = {
       padconnectionstatus.disconnected(message);
     }
     const newFullyConnected = !!padconnectionstatus.isFullyConnected();
-    if (newFullyConnected != oldFullyConnected) {
+    if (newFullyConnected !== oldFullyConnected) {
       pad.handleIsFullyConnected(newFullyConnected, wasConnecting);
     }
   },
-  handleIsFullyConnected(isConnected, isInitialConnect) {
+  handleIsFullyConnected: (isConnected, isInitialConnect) => {
     pad.determineChatVisibility(isConnected && !isInitialConnect);
     pad.determineChatAndUsersVisibility(isConnected && !isInitialConnect);
     pad.determineAuthorshipColorsVisibility();
@@ -625,7 +663,7 @@ var pad = {
       padeditbar.toggleDropDown('none');
     }, 1000);
   },
-  determineChatVisibility(asNowConnectedFeedback) {
+  determineChatVisibility: (asNowConnectedFeedback) => {
     const chatVisCookie = padcookie.getPref('chatAlwaysVisible');
     if (chatVisCookie) { // if the cookie is set for chat always visible
       chat.stickToScreen(true); // stick it to the screen
@@ -634,7 +672,7 @@ var pad = {
       $('#options-stickychat').prop('checked', false); // set the checkbox for off
     }
   },
-  determineChatAndUsersVisibility(asNowConnectedFeedback) {
+  determineChatAndUsersVisibility: (asNowConnectedFeedback) => {
     const chatAUVisCookie = padcookie.getPref('chatAndUsersVisible');
     if (chatAUVisCookie) { // if the cookie is set for chat always visible
       chat.chatAndUsers(true); // stick it to the screen
@@ -643,7 +681,7 @@ var pad = {
       $('#options-chatandusers').prop('checked', false); // set the checkbox for off
     }
   },
-  determineAuthorshipColorsVisibility() {
+  determineAuthorshipColorsVisibility: () => {
     const authColCookie = padcookie.getPref('showAuthorshipColors');
     if (authColCookie) {
       pad.changeViewOption('showAuthorColors', true);
@@ -652,14 +690,14 @@ var pad = {
       $('#options-colorscheck').prop('checked', false);
     }
   },
-  handleCollabAction(action) {
-    if (action == 'commitPerformed') {
+  handleCollabAction: (action) => {
+    if (action === 'commitPerformed') {
       padeditbar.setSyncStatus('syncing');
-    } else if (action == 'newlyIdle') {
+    } else if (action === 'newlyIdle') {
       padeditbar.setSyncStatus('done');
     }
   },
-  asyncSendDiagnosticInfo() {
+  asyncSendDiagnosticInfo: () => {
     window.setTimeout(() => {
       $.ajax(
           {
@@ -668,32 +706,29 @@ var pad = {
             data: {
               diagnosticInfo: JSON.stringify(pad.diagnosticInfo),
             },
-            success() {},
-            error() {},
+            success: () => {},
+            error: () => {},
           });
     }, 0);
   },
-  forceReconnect() {
+  forceReconnect: () => {
     $('form#reconnectform input.padId').val(pad.getPadId());
     pad.diagnosticInfo.collabDiagnosticInfo = pad.collabClient.getDiagnosticInfo();
     $('form#reconnectform input.diagnosticInfo').val(JSON.stringify(pad.diagnosticInfo));
-    $('form#reconnectform input.missedChanges').val(JSON.stringify(pad.collabClient.getMissedChanges()));
+    $('form#reconnectform input.missedChanges')
+        .val(JSON.stringify(pad.collabClient.getMissedChanges()));
     $('form#reconnectform').submit();
   },
   // this is called from code put into a frame from the server:
-  handleImportExportFrameCall(callName, varargs) {
+  handleImportExportFrameCall: (callName, varargs) => {
     padimpexp.handleFrameCall.call(padimpexp, callName, Array.prototype.slice.call(arguments, 1));
   },
-  callWhenNotCommitting(f) {
+  callWhenNotCommitting: (f) => {
     pad.collabClient.callWhenNotCommitting(f);
   },
-  getCollabRevisionNumber() {
-    return pad.collabClient.getCurrentRevisionNumber();
-  },
-  isFullyConnected() {
-    return padconnectionstatus.isFullyConnected();
-  },
-  addHistoricalAuthors(data) {
+  getCollabRevisionNumber: () => pad.collabClient.getCurrentRevisionNumber(),
+  isFullyConnected: () => padconnectionstatus.isFullyConnected(),
+  addHistoricalAuthors: (data) => {
     if (!pad.collabClient) {
       window.setTimeout(() => {
         pad.addHistoricalAuthors(data);
@@ -704,11 +739,9 @@ var pad = {
   },
 };
 
-function init() {
-  return pad.init();
-}
+const init = () => pad.init();
 
-var settings = {
+const settings = {
   LineNumbersDisabled: false,
   noColors: false,
   useMonospaceFontGlobal: false,
@@ -718,6 +751,7 @@ var settings = {
 };
 
 pad.settings = settings;
+
 exports.baseURL = '';
 exports.settings = settings;
 exports.randomString = randomString;
diff --git a/src/static/js/pad_automatic_reconnect.js b/src/static/js/pad_automatic_reconnect.js
index 8edd09b38..db803e896 100644
--- a/src/static/js/pad_automatic_reconnect.js
+++ b/src/static/js/pad_automatic_reconnect.js
@@ -1,4 +1,6 @@
-exports.showCountDownTimerToReconnectOnModal = function ($modal, pad) {
+'use strict';
+
+exports.showCountDownTimerToReconnectOnModal = ($modal, pad) => {
   if (clientVars.automaticReconnectionTimeout && $modal.is('.with_reconnect_timer')) {
     createCountDownElementsIfNecessary($modal);
 
@@ -13,7 +15,7 @@ exports.showCountDownTimerToReconnectOnModal = function ($modal, pad) {
   }
 };
 
-var createCountDownElementsIfNecessary = function ($modal) {
+const createCountDownElementsIfNecessary = ($modal) => {
   const elementsDoNotExist = $modal.find('#cancelreconnect').length === 0;
   if (elementsDoNotExist) {
     const $defaultMessage = $modal.find('#defaulttext');
@@ -45,12 +47,13 @@ var createCountDownElementsIfNecessary = function ($modal) {
   }
 };
 
-var localize = function ($element) {
+const localize = ($element) => {
   html10n.translateElement(html10n.translations, $element.get(0));
 };
 
-var createTimerForModal = function ($modal, pad) {
-  const timeUntilReconnection = clientVars.automaticReconnectionTimeout * reconnectionTries.nextTry();
+const createTimerForModal = ($modal, pad) => {
+  const timeUntilReconnection =
+      clientVars.automaticReconnectionTimeout * reconnectionTries.nextTry();
   const timer = new CountDownTimer(timeUntilReconnection);
 
   timer.onTick((minutes, seconds) => {
@@ -68,23 +71,23 @@ var createTimerForModal = function ($modal, pad) {
   return timer;
 };
 
-var disableAutomaticReconnection = function ($modal) {
+const disableAutomaticReconnection = ($modal) => {
   toggleAutomaticReconnectionOption($modal, true);
 };
-var enableAutomaticReconnection = function ($modal) {
+const enableAutomaticReconnection = ($modal) => {
   toggleAutomaticReconnectionOption($modal, false);
 };
-var toggleAutomaticReconnectionOption = function ($modal, disableAutomaticReconnect) {
+const toggleAutomaticReconnectionOption = ($modal, disableAutomaticReconnect) => {
   $modal.find('#cancelreconnect, .reconnecttimer').toggleClass('hidden', disableAutomaticReconnect);
   $modal.find('#defaulttext').toggleClass('hidden', !disableAutomaticReconnect);
 };
 
-var waitUntilClientCanConnectToServerAndThen = function (callback, pad) {
+const waitUntilClientCanConnectToServerAndThen = (callback, pad) => {
   whenConnectionIsRestablishedWithServer(callback, pad);
   pad.socket.connect();
 };
 
-var whenConnectionIsRestablishedWithServer = function (callback, pad) {
+const whenConnectionIsRestablishedWithServer = (callback, pad) => {
   // only add listener for the first try, don't need to add another listener
   // on every unsuccessful try
   if (reconnectionTries.counter === 1) {
@@ -92,11 +95,11 @@ var whenConnectionIsRestablishedWithServer = function (callback, pad) {
   }
 };
 
-var forceReconnection = function ($modal) {
+const forceReconnection = ($modal) => {
   $modal.find('#forcereconnect').click();
 };
 
-var updateCountDownTimerMessage = function ($modal, minutes, seconds) {
+const updateCountDownTimerMessage = ($modal, minutes, seconds) => {
   minutes = minutes < 10 ? `0${minutes}` : minutes;
   seconds = seconds < 10 ? `0${seconds}` : seconds;
 
@@ -105,7 +108,7 @@ var updateCountDownTimerMessage = function ($modal, minutes, seconds) {
 
 // store number of tries to reconnect to server, in order to increase time to wait
 // until next try
-var reconnectionTries = {
+const reconnectionTries = {
   counter: 0,
 
   nextTry() {
@@ -119,8 +122,9 @@ var reconnectionTries = {
 
 // Timer based on http://stackoverflow.com/a/20618517.
 // duration: how many **seconds** until the timer ends
-// granularity (optional): how many **milliseconds** between each 'tick' of timer. Default: 1000ms (1s)
-var CountDownTimer = function (duration, granularity) {
+// granularity (optional): how many **milliseconds**
+// between each 'tick' of timer. Default: 1000ms (1s)
+const CountDownTimer = function (duration, granularity) {
   this.duration = duration;
   this.granularity = granularity || 1000;
   this.running = false;
@@ -137,8 +141,7 @@ CountDownTimer.prototype.start = function () {
   const start = Date.now();
   const that = this;
   let diff;
-
-  (function timer() {
+  const timer = () => {
     diff = that.duration - Math.floor((Date.now() - start) / 1000);
 
     if (diff > 0) {
@@ -149,7 +152,8 @@ CountDownTimer.prototype.start = function () {
       that.tick(0);
       that.expire();
     }
-  }());
+  };
+  timer();
 };
 
 CountDownTimer.prototype.tick = function (diff) {
@@ -184,9 +188,7 @@ CountDownTimer.prototype.cancel = function () {
   return this;
 };
 
-CountDownTimer.parse = function (seconds) {
-  return {
-    minutes: (seconds / 60) | 0,
-    seconds: (seconds % 60) | 0,
-  };
-};
+CountDownTimer.parse = (seconds) => ({
+  minutes: (seconds / 60) | 0,
+  seconds: (seconds % 60) | 0,
+});
diff --git a/src/static/js/pad_connectionstatus.js b/src/static/js/pad_connectionstatus.js
index 54d7dc760..1282d488c 100644
--- a/src/static/js/pad_connectionstatus.js
+++ b/src/static/js/pad_connectionstatus.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
@@ -22,25 +24,25 @@
 
 const padmodals = require('./pad_modals').padmodals;
 
-const padconnectionstatus = (function () {
+const padconnectionstatus = (() => {
   let status = {
     what: 'connecting',
   };
 
   const self = {
-    init() {
+    init: () => {
       $('button#forcereconnect').click(() => {
         window.location.reload();
       });
     },
-    connected() {
+    connected: () => {
       status = {
         what: 'connected',
       };
       padmodals.showModal('connected');
       padmodals.hideOverlay();
     },
-    reconnecting() {
+    reconnecting: () => {
       status = {
         what: 'reconnecting',
       };
@@ -48,8 +50,8 @@ const padconnectionstatus = (function () {
       padmodals.showModal('reconnecting');
       padmodals.showOverlay();
     },
-    disconnected(msg) {
-      if (status.what == 'disconnected') return;
+    disconnected: (msg) => {
+      if (status.what === 'disconnected') return;
 
       status = {
         what: 'disconnected',
@@ -81,14 +83,10 @@ const padconnectionstatus = (function () {
       padmodals.showModal(k);
       padmodals.showOverlay();
     },
-    isFullyConnected() {
-      return status.what == 'connected';
-    },
-    getStatus() {
-      return status;
-    },
+    isFullyConnected: () => status.what === 'connected',
+    getStatus: () => status,
   };
   return self;
-}());
+})();
 
 exports.padconnectionstatus = padconnectionstatus;
diff --git a/src/static/js/pad_cookie.js b/src/static/js/pad_cookie.js
index f3dedf03c..620d41735 100644
--- a/src/static/js/pad_cookie.js
+++ b/src/static/js/pad_cookie.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * Copyright 2009 Google Inc.
  *
diff --git a/src/static/js/pad_editbar.js b/src/static/js/pad_editbar.js
index dae96b192..788d5ecd0 100644
--- a/src/static/js/pad_editbar.js
+++ b/src/static/js/pad_editbar.js
@@ -1,4 +1,5 @@
 'use strict';
+
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
diff --git a/src/static/js/pad_editor.js b/src/static/js/pad_editor.js
index 912c50f64..b7b94f720 100644
--- a/src/static/js/pad_editor.js
+++ b/src/static/js/pad_editor.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
@@ -24,26 +26,26 @@ const Cookies = require('./pad_utils').Cookies;
 const padcookie = require('./pad_cookie').padcookie;
 const padutils = require('./pad_utils').padutils;
 
-const padeditor = (function () {
+const padeditor = (() => {
   let Ace2Editor = undefined;
   let pad = undefined;
   let settings = undefined;
 
-  var self = {
+  const self = {
     ace: null,
     // this is accessed directly from other files
     viewZoom: 100,
-    init(readyFunc, initialViewOptions, _pad) {
+    init: (readyFunc, initialViewOptions, _pad) => {
       Ace2Editor = require('./ace').Ace2Editor;
       pad = _pad;
       settings = pad.settings;
 
-      function aceReady() {
+      const aceReady = () => {
         $('#editorloadingbox').hide();
         if (readyFunc) {
           readyFunc();
         }
-      }
+      };
 
       self.ace = new Ace2Editor();
       self.ace.init('editorcontainer', '', aceReady);
@@ -57,7 +59,7 @@ const padeditor = (function () {
       // view bar
       $('#viewbarcontents').show();
     },
-    initViewOptions() {
+    initViewOptions: () => {
       // Line numbers
       padutils.bindCheckboxChange($('#options-linenoscheck'), () => {
         pad.changeViewOption('showLineNumbers', padutils.getCheckbox($('#options-linenoscheck')));
@@ -74,8 +76,8 @@ const padeditor = (function () {
         pad.changeViewOption('rtlIsTrue', padutils.getCheckbox($('#options-rtlcheck')));
       });
       html10n.bind('localized', () => {
-        pad.changeViewOption('rtlIsTrue', ('rtl' == html10n.getDirection()));
-        padutils.setCheckbox($('#options-rtlcheck'), ('rtl' == html10n.getDirection()));
+        pad.changeViewOption('rtlIsTrue', ('rtl' === html10n.getDirection()));
+        padutils.setCheckbox($('#options-rtlcheck'), ('rtl' === html10n.getDirection()));
       });
 
       // font family change
@@ -87,9 +89,10 @@ const padeditor = (function () {
       html10n.bind('localized', () => {
         $('#languagemenu').val(html10n.getLanguage());
         // translate the value of 'unnamed' and 'Enter your name' textboxes in the userlist
-        // this does not interfere with html10n's normal value-setting because html10n just ingores <input>s
-        // also, a value which has been set by the user will be not overwritten since a user-edited <input>
-        // does *not* have the editempty-class
+        // this does not interfere with html10n's normal value-setting because
+        // html10n just ingores <input>s
+        // also, a value which has been set by the user will be not overwritten
+        // since a user-edited <input> does *not* have the editempty-class
         $('input[data-l10n-id]').each((key, input) => {
           input = $(input);
           if (input.hasClass('editempty')) {
@@ -106,17 +109,17 @@ const padeditor = (function () {
         }
       });
     },
-    setViewOptions(newOptions) {
-      function getOption(key, defaultValue) {
+    setViewOptions: (newOptions) => {
+      const getOption = (key, defaultValue) => {
         const value = String(newOptions[key]);
-        if (value == 'true') return true;
-        if (value == 'false') return false;
+        if (value === 'true') return true;
+        if (value === 'false') return false;
         return defaultValue;
-      }
+      };
 
       let v;
 
-      v = getOption('rtlIsTrue', ('rtl' == html10n.getDirection()));
+      v = getOption('rtlIsTrue', ('rtl' === html10n.getDirection()));
       self.ace.setProperty('rtlIsTrue', v);
       padutils.setCheckbox($('#options-rtlcheck'), v);
 
@@ -137,29 +140,29 @@ const padeditor = (function () {
 
       self.ace.setProperty('textface', newOptions.padFontFamily || '');
     },
-    dispose() {
+    dispose: () => {
       if (self.ace) {
         self.ace.destroy();
         self.ace = null;
       }
     },
-    enable() {
+    enable: () => {
       if (self.ace) {
         self.ace.setEditable(true);
       }
     },
-    disable() {
+    disable: () => {
       if (self.ace) {
         self.ace.setProperty('grayedOut', true);
         self.ace.setEditable(false);
       }
     },
-    restoreRevisionText(dataFromServer) {
+    restoreRevisionText: (dataFromServer) => {
       pad.addHistoricalAuthors(dataFromServer.historicalAuthorData);
       self.ace.importAText(dataFromServer.atext, dataFromServer.apool, true);
     },
   };
   return self;
-}());
+})();
 
 exports.padeditor = padeditor;
diff --git a/src/static/js/pad_impexp.js b/src/static/js/pad_impexp.js
index 9c5dd076e..a44c69d8a 100644
--- a/src/static/js/pad_impexp.js
+++ b/src/static/js/pad_impexp.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
@@ -20,24 +22,27 @@
  * limitations under the License.
  */
 
-const padimpexp = (function () {
+const padimpexp = (() => {
   // /// import
   let currentImportTimer = null;
 
-  function addImportFrames() {
+  const addImportFrames = () => {
     $('#import .importframe').remove();
-    const iframe = $('<iframe style="display: none;" name="importiframe" class="importframe"></iframe>');
+    const iframe = $('<iframe>')
+        .css('display', 'none')
+        .attr('name', 'importiframe')
+        .addClass('importframe');
     $('#import').append(iframe);
-  }
+  };
 
-  function fileInputUpdated() {
+  const fileInputUpdated = () => {
     $('#importsubmitinput').addClass('throbbold');
     $('#importformfilediv').addClass('importformenabled');
     $('#importsubmitinput').removeAttr('disabled');
     $('#importmessagefail').fadeOut('fast');
-  }
+  };
 
-  function fileInputSubmit() {
+  const fileInputSubmit = () => {
     $('#importmessagefail').fadeOut('fast');
     const ret = window.confirm(html10n.get('pad.impexp.confirmimport'));
     if (ret) {
@@ -64,13 +69,13 @@ const padimpexp = (function () {
       $('#importstatusball').show();
     }
     return ret;
-  }
+  };
 
-  function importFailed(msg) {
+  const importFailed = (msg) => {
     importErrorMessage(msg);
-  }
+  };
 
-  function importDone() {
+  const importDone = () => {
     $('#importsubmitinput').removeAttr('disabled').val(html10n.get('pad.impexp.importbutton'));
     window.setTimeout(() => {
       $('#importfileinput').removeAttr('disabled');
@@ -78,16 +83,16 @@ const padimpexp = (function () {
     $('#importstatusball').hide();
     importClearTimeout();
     addImportFrames();
-  }
+  };
 
-  function importClearTimeout() {
+  const importClearTimeout = () => {
     if (currentImportTimer) {
       window.clearTimeout(currentImportTimer);
       currentImportTimer = null;
     }
-  }
+  };
 
-  function importErrorMessage(status) {
+  const importErrorMessage = (status) => {
     let msg = '';
 
     if (status === 'convertFailed') {
@@ -102,9 +107,11 @@ const padimpexp = (function () {
       msg = html10n.get('pad.impexp.permission');
     }
 
-    function showError(fade) {
-      $('#importmessagefail').html(`<strong style="color: red">${html10n.get('pad.impexp.importfailed')}:</strong> ${msg || html10n.get('pad.impexp.copypaste', '')}`)[(fade ? 'fadeIn' : 'show')]();
-    }
+    const showError = (fade) => {
+      $('#importmessagefail').html(
+          `<strong style="color: red">${html10n.get('pad.impexp.importfailed')}:</strong> ` +
+          `${msg || html10n.get('pad.impexp.copypaste', '')}`)[(fade ? 'fadeIn' : 'show')]();
+    };
 
     if ($('#importexport .importmessage').is(':visible')) {
       $('#importmessagesuccess').fadeOut('fast');
@@ -114,7 +121,7 @@ const padimpexp = (function () {
     } else {
       showError();
     }
-  }
+  };
 
   // /// export
 
@@ -134,16 +141,17 @@ const padimpexp = (function () {
   }
 
   // ///
-  var pad = undefined;
+  let pad = undefined;
   const self = {
-    init(_pad) {
+    init: (_pad) => {
       pad = _pad;
 
       // get /p/padname
       // if /p/ isn't available due to a rewrite we use the clientVars padId
-      const pad_root_path = new RegExp(/.*\/p\/[^\/]+/).exec(document.location.pathname) || clientVars.padId;
+      const padRootPath = /.*\/p\/[^/]+/.exec(document.location.pathname) || clientVars.padId;
       // get http://example.com/p/padname without Params
-      const pad_root_url = `${document.location.protocol}//${document.location.host}${document.location.pathname}`;
+      const dl = document.location;
+      const padRootUrl = `${dl.protocol}//${dl.host}${dl.pathname}`;
 
       // i10l buttom import
       $('#importsubmitinput').val(html10n.get('pad.impexp.importbutton'));
@@ -152,32 +160,32 @@ const padimpexp = (function () {
       });
 
       // build the export links
-      $('#exporthtmla').attr('href', `${pad_root_path}/export/html`);
-      $('#exportetherpada').attr('href', `${pad_root_path}/export/etherpad`);
-      $('#exportplaina').attr('href', `${pad_root_path}/export/txt`);
+      $('#exporthtmla').attr('href', `${padRootPath}/export/html`);
+      $('#exportetherpada').attr('href', `${padRootPath}/export/etherpad`);
+      $('#exportplaina').attr('href', `${padRootPath}/export/txt`);
 
       // activate action to import in the form
-      $('#importform').attr('action', `${pad_root_url}/import`);
+      $('#importform').attr('action', `${padRootUrl}/import`);
 
       // hide stuff thats not avaible if abiword/soffice is disabled
-      if (clientVars.exportAvailable == 'no') {
+      if (clientVars.exportAvailable === 'no') {
         $('#exportworda').remove();
         $('#exportpdfa').remove();
         $('#exportopena').remove();
 
         $('#importmessageabiword').show();
-      } else if (clientVars.exportAvailable == 'withoutPDF') {
+      } else if (clientVars.exportAvailable === 'withoutPDF') {
         $('#exportpdfa').remove();
 
-        $('#exportworda').attr('href', `${pad_root_path}/export/doc`);
-        $('#exportopena').attr('href', `${pad_root_path}/export/odt`);
+        $('#exportworda').attr('href', `${padRootPath}/export/doc`);
+        $('#exportopena').attr('href', `${padRootPath}/export/odt`);
 
         $('#importexport').css({height: '142px'});
         $('#importexportline').css({height: '142px'});
       } else {
-        $('#exportworda').attr('href', `${pad_root_path}/export/doc`);
-        $('#exportpdfa').attr('href', `${pad_root_path}/export/pdf`);
-        $('#exportopena').attr('href', `${pad_root_path}/export/odt`);
+        $('#exportworda').attr('href', `${padRootPath}/export/doc`);
+        $('#exportpdfa').attr('href', `${padRootPath}/export/pdf`);
+        $('#exportopena').attr('href', `${padRootPath}/export/odt`);
       }
 
       addImportFrames();
@@ -185,7 +193,7 @@ const padimpexp = (function () {
       $('#importform').unbind('submit').submit(fileInputSubmit);
       $('.disabledexport').click(cantExport);
     },
-    handleFrameCall(directDatabaseAccess, status) {
+    handleFrameCall: (directDatabaseAccess, status) => {
       if (directDatabaseAccess === 'undefined') directDatabaseAccess = false;
       if (status !== 'ok') {
         importFailed(status);
@@ -201,18 +209,18 @@ const padimpexp = (function () {
 
       importDone();
     },
-    disable() {
+    disable: () => {
       $('#impexp-disabled-clickcatcher').show();
       $('#import').css('opacity', 0.5);
       $('#impexp-export').css('opacity', 0.5);
     },
-    enable() {
+    enable: () => {
       $('#impexp-disabled-clickcatcher').hide();
       $('#import').css('opacity', 1);
       $('#impexp-export').css('opacity', 1);
     },
   };
   return self;
-}());
+})();
 
 exports.padimpexp = padimpexp;
diff --git a/src/static/js/pad_modals.js b/src/static/js/pad_modals.js
index f7cf2ab99..99d4dd6ac 100644
--- a/src/static/js/pad_modals.js
+++ b/src/static/js/pad_modals.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
@@ -23,13 +25,13 @@
 const padeditbar = require('./pad_editbar').padeditbar;
 const automaticReconnect = require('./pad_automatic_reconnect');
 
-const padmodals = (function () {
+const padmodals = (() => {
   let pad = undefined;
   const self = {
-    init(_pad) {
+    init: (_pad) => {
       pad = _pad;
     },
-    showModal(messageId) {
+    showModal: (messageId) => {
       padeditbar.toggleDropDown('none', () => {
         $('#connectivity .visible').removeClass('visible');
         $(`#connectivity .${messageId}`).addClass('visible');
@@ -40,15 +42,15 @@ const padmodals = (function () {
         padeditbar.toggleDropDown('connectivity');
       });
     },
-    showOverlay() {
+    showOverlay: () => {
       // Prevent the user to interact with the toolbar. Useful when user is disconnected for example
       $('#toolbar-overlay').show();
     },
-    hideOverlay() {
+    hideOverlay: () => {
       $('#toolbar-overlay').hide();
     },
   };
   return self;
-}());
+})();
 
 exports.padmodals = padmodals;
diff --git a/src/static/js/pad_savedrevs.js b/src/static/js/pad_savedrevs.js
index ba0c51de9..b5868f699 100644
--- a/src/static/js/pad_savedrevs.js
+++ b/src/static/js/pad_savedrevs.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * Copyright 2012 Peter 'Pita' Martischka
  *
@@ -16,13 +18,14 @@
 
 let pad;
 
-exports.saveNow = function () {
+exports.saveNow = () => {
   pad.collabClient.sendMessage({type: 'SAVE_REVISION'});
   $.gritter.add({
     // (string | mandatory) the heading of the notification
-    title: _('pad.savedrevs.marked'),
+    title: html10n.get('pad.savedrevs.marked'),
     // (string | mandatory) the text inside the notification
-    text: _('pad.savedrevs.timeslider') || 'You can view saved revisions in the timeslider',
+    text: html10n.get('pad.savedrevs.timeslider') ||
+        'You can view saved revisions in the timeslider',
     // (bool | optional) if you want it to fade out on its own or just sit there
     sticky: false,
     time: 3000,
@@ -30,6 +33,6 @@ exports.saveNow = function () {
   });
 };
 
-exports.init = function (_pad) {
+exports.init = (_pad) => {
   pad = _pad;
 };
diff --git a/src/static/js/pad_userlist.js b/src/static/js/pad_userlist.js
index 6285ffad2..d596290f6 100644
--- a/src/static/js/pad_userlist.js
+++ b/src/static/js/pad_userlist.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
@@ -22,13 +24,12 @@
 
 const padutils = require('./pad_utils').padutils;
 const hooks = require('./pluginfw/hooks');
+const browser = require('./browser');
 
 let myUserInfo = {};
 
 let colorPickerOpen = false;
 let colorPickerSetup = false;
-let previousColorId = 0;
-
 
 const paduserlist = (function () {
   const rowManager = (function () {
@@ -36,9 +37,7 @@ const paduserlist = (function () {
     // their insertion, removal, and reordering.  It manipulates TD height
     // and TD opacity.
 
-    function nextRowId() {
-      return `usertr${nextRowId.counter++}`;
-    }
+    const nextRowId = () => `usertr${nextRowId.counter++}`;
     nextRowId.counter = 1;
     // objects are shared; fields are "domId","data","animationStep"
     const rowsFadingOut = []; // unordered set
@@ -47,20 +46,67 @@ const paduserlist = (function () {
     const ANIMATION_START = -12; // just starting to fade in
     const ANIMATION_END = 12; // just finishing fading out
 
+    const animateStep = () => {
+      // animation must be symmetrical
+      for (let i = rowsFadingIn.length - 1; i >= 0; i--) { // backwards to allow removal
+        const row = rowsFadingIn[i];
+        const step = ++row.animationStep;
+        const animHeight = getAnimationHeight(step, row.animationPower);
+        const node = rowNode(row);
+        const baseOpacity = (row.opacity === undefined ? 1 : row.opacity);
+        if (step <= -OPACITY_STEPS) {
+          node.find('td').height(animHeight);
+        } else if (step === -OPACITY_STEPS + 1) {
+          node.empty().append(createUserRowTds(animHeight, row.data))
+              .find('td').css('opacity', baseOpacity * 1 / OPACITY_STEPS);
+        } else if (step < 0) {
+          node.find('td').css('opacity', baseOpacity * (OPACITY_STEPS - (-step)) / OPACITY_STEPS)
+              .height(animHeight);
+        } else if (step === 0) {
+          // set HTML in case modified during animation
+          node.empty().append(createUserRowTds(animHeight, row.data))
+              .find('td').css('opacity', baseOpacity * 1).height(animHeight);
+          rowsFadingIn.splice(i, 1); // remove from set
+        }
+      }
+      for (let i = rowsFadingOut.length - 1; i >= 0; i--) { // backwards to allow removal
+        const row = rowsFadingOut[i];
+        const step = ++row.animationStep;
+        const node = rowNode(row);
+        const animHeight = getAnimationHeight(step, row.animationPower);
+        const baseOpacity = (row.opacity === undefined ? 1 : row.opacity);
+        if (step < OPACITY_STEPS) {
+          node.find('td').css('opacity', baseOpacity * (OPACITY_STEPS - step) / OPACITY_STEPS)
+              .height(animHeight);
+        } else if (step === OPACITY_STEPS) {
+          node.empty().append(createEmptyRowTds(animHeight));
+        } else if (step <= ANIMATION_END) {
+          node.find('td').height(animHeight);
+        } else {
+          rowsFadingOut.splice(i, 1); // remove from set
+          node.remove();
+        }
+      }
 
-    function getAnimationHeight(step, power) {
+      handleOtherUserInputs();
+
+      return (rowsFadingIn.length > 0) || (rowsFadingOut.length > 0); // is more to do
+    };
+
+    const getAnimationHeight = (step, power) => {
       let a = Math.abs(step / 12);
-      if (power == 2) a *= a;
-      else if (power == 3) a = a * a * a;
-      else if (power == 4) a = a * a * a * a;
-      else if (power >= 5) a = a * a * a * a * a;
+      if (power === 2) a **= 2;
+      else if (power === 3) a **= 3;
+      else if (power === 4) a **= 4;
+      else if (power >= 5) a **= 5;
       return Math.round(26 * (1 - a));
-    }
+    };
     const OPACITY_STEPS = 6;
 
     const ANIMATION_STEP_TIME = 20;
     const LOWER_FRAMERATE_FACTOR = 2;
-    const scheduleAnimation = padutils.makeAnimationScheduler(animateStep, ANIMATION_STEP_TIME, LOWER_FRAMERATE_FACTOR).scheduleAnimation;
+    const {scheduleAnimation} =
+        padutils.makeAnimationScheduler(animateStep, ANIMATION_STEP_TIME, LOWER_FRAMERATE_FACTOR);
 
     const NUMCOLS = 4;
 
@@ -72,11 +118,9 @@ const paduserlist = (function () {
         .css('border', 0)
         .css('height', `${height}px`);
 
-    function isNameEditable(data) {
-      return (!data.name) && (data.status != 'Disconnected');
-    }
+    const isNameEditable = (data) => (!data.name) && (data.status !== 'Disconnected');
 
-    function replaceUserRowContents(tr, height, data) {
+    const replaceUserRowContents = (tr, height, data) => {
       const tds = createUserRowTds(height, data);
       if (isNameEditable(data) && tr.find('td.usertdname input:enabled').length > 0) {
         // preserve input field node
@@ -93,7 +137,7 @@ const paduserlist = (function () {
         tr.empty().append(tds);
       }
       return tr;
-    }
+    };
 
     const createUserRowTds = (height, data) => {
       let name;
@@ -105,7 +149,7 @@ const paduserlist = (function () {
             .attr('type', 'text')
             .addClass('editempty')
             .addClass('newinput')
-            .attr('value', _('pad.userlist.unnamed'));
+            .attr('value', html10n.get('pad.userlist.unnamed'));
         if (isNameEditable(data)) name.attr('disabled', 'disabled');
       }
       return $()
@@ -131,19 +175,17 @@ const paduserlist = (function () {
         .attr('id', id)
         .append(contents);
 
-    function rowNode(row) {
-      return $(`#${row.domId}`);
-    }
+    const rowNode = (row) => $(`#${row.domId}`);
 
-    function handleRowData(row) {
-      if (row.data && row.data.status == 'Disconnected') {
+    const handleRowData = (row) => {
+      if (row.data && row.data.status === 'Disconnected') {
         row.opacity = 0.5;
       } else {
         delete row.opacity;
       }
-    }
+    };
 
-    function handleOtherUserInputs() {
+    const handleOtherUserInputs = () => {
       // handle 'INPUT' elements for naming other unnamed users
       $('#otheruserstable input.newinput').each(function () {
         const input = $(this);
@@ -156,12 +198,12 @@ const paduserlist = (function () {
           }
         }
       }).removeClass('newinput');
-    }
+    };
 
     // animationPower is 0 to skip animation, 1 for linear, 2 for quadratic, etc.
 
 
-    function insertRow(position, data, animationPower) {
+    const insertRow = (position, data, animationPower) => {
       position = Math.max(0, Math.min(rowsPresent.length, position));
       animationPower = (animationPower === undefined ? 4 : animationPower);
 
@@ -177,7 +219,7 @@ const paduserlist = (function () {
       handleRowData(row);
       rowsPresent.splice(position, 0, row);
       let tr;
-      if (animationPower == 0) {
+      if (animationPower === 0) {
         tr = createRow(domId, createUserRowTds(getAnimationHeight(0), data), authorId);
         row.animationStep = 0;
       } else {
@@ -185,41 +227,43 @@ const paduserlist = (function () {
         tr = createRow(domId, createEmptyRowTds(getAnimationHeight(ANIMATION_START)), authorId);
       }
       $('table#otheruserstable').show();
-      if (position == 0) {
+      if (position === 0) {
         $('table#otheruserstable').prepend(tr);
       } else {
         rowNode(rowsPresent[position - 1]).after(tr);
       }
 
-      if (animationPower != 0) {
+      if (animationPower !== 0) {
         scheduleAnimation();
       }
 
       handleOtherUserInputs();
 
       return row;
-    }
+    };
 
-    function updateRow(position, data) {
+    const updateRow = (position, data) => {
       const row = rowsPresent[position];
       if (row) {
         row.data = data;
         handleRowData(row);
-        if (row.animationStep == 0) {
+        if (row.animationStep === 0) {
           // not currently animating
           const tr = rowNode(row);
-          replaceUserRowContents(tr, getAnimationHeight(0), row.data).find('td').css('opacity', (row.opacity === undefined ? 1 : row.opacity));
+          replaceUserRowContents(tr, getAnimationHeight(0), row.data)
+              .find('td')
+              .css('opacity', (row.opacity === undefined ? 1 : row.opacity));
           handleOtherUserInputs();
         }
       }
-    }
+    };
 
-    function removeRow(position, animationPower) {
+    const removeRow = (position, animationPower) => {
       animationPower = (animationPower === undefined ? 4 : animationPower);
       const row = rowsPresent[position];
       if (row) {
         rowsPresent.splice(position, 1); // remove
-        if (animationPower == 0) {
+        if (animationPower === 0) {
           rowNode(row).remove();
         } else {
           row.animationStep = -row.animationStep; // use symmetry
@@ -231,65 +275,20 @@ const paduserlist = (function () {
       if (rowsPresent.length === 0) {
         $('table#otheruserstable').hide();
       }
-    }
+    };
 
     // newPosition is position after the row has been removed
 
 
-    function moveRow(oldPosition, newPosition, animationPower) {
+    const moveRow = (oldPosition, newPosition, animationPower) => {
       animationPower = (animationPower === undefined ? 1 : animationPower); // linear is best
       const row = rowsPresent[oldPosition];
-      if (row && oldPosition != newPosition) {
+      if (row && oldPosition !== newPosition) {
         const rowData = row.data;
         removeRow(oldPosition, animationPower);
         insertRow(newPosition, rowData, animationPower);
       }
-    }
-
-    function animateStep() {
-      // animation must be symmetrical
-      for (var i = rowsFadingIn.length - 1; i >= 0; i--) { // backwards to allow removal
-        var row = rowsFadingIn[i];
-        var step = ++row.animationStep;
-        var animHeight = getAnimationHeight(step, row.animationPower);
-        var node = rowNode(row);
-        var baseOpacity = (row.opacity === undefined ? 1 : row.opacity);
-        if (step <= -OPACITY_STEPS) {
-          node.find('td').height(animHeight);
-        } else if (step == -OPACITY_STEPS + 1) {
-          node.empty().append(createUserRowTds(animHeight, row.data))
-              .find('td').css('opacity', baseOpacity * 1 / OPACITY_STEPS);
-        } else if (step < 0) {
-          node.find('td').css('opacity', baseOpacity * (OPACITY_STEPS - (-step)) / OPACITY_STEPS).height(animHeight);
-        } else if (step == 0) {
-          // set HTML in case modified during animation
-          node.empty().append(createUserRowTds(animHeight, row.data))
-              .find('td').css('opacity', baseOpacity * 1).height(animHeight);
-          rowsFadingIn.splice(i, 1); // remove from set
-        }
-      }
-      for (var i = rowsFadingOut.length - 1; i >= 0; i--) { // backwards to allow removal
-        var row = rowsFadingOut[i];
-        var step = ++row.animationStep;
-        var node = rowNode(row);
-        var animHeight = getAnimationHeight(step, row.animationPower);
-        var baseOpacity = (row.opacity === undefined ? 1 : row.opacity);
-        if (step < OPACITY_STEPS) {
-          node.find('td').css('opacity', baseOpacity * (OPACITY_STEPS - step) / OPACITY_STEPS).height(animHeight);
-        } else if (step == OPACITY_STEPS) {
-          node.empty().append(createEmptyRowTds(animHeight));
-        } else if (step <= ANIMATION_END) {
-          node.find('td').height(animHeight);
-        } else {
-          rowsFadingOut.splice(i, 1); // remove from set
-          node.remove();
-        }
-      }
-
-      handleOtherUserInputs();
-
-      return (rowsFadingIn.length > 0) || (rowsFadingOut.length > 0); // is more to do
-    }
+    };
 
     const self = {
       insertRow,
@@ -302,7 +301,7 @@ const paduserlist = (function () {
   const otherUsersInfo = [];
   const otherUsersData = [];
 
-  function rowManagerMakeNameEditor(jnode, userId) {
+  const rowManagerMakeNameEditor = (jnode, userId) => {
     setUpEditable(jnode, () => {
       const existingIndex = findExistingIndex(userId);
       if (existingIndex >= 0) {
@@ -313,26 +312,26 @@ const paduserlist = (function () {
     }, (newName) => {
       if (!newName) {
         jnode.addClass('editempty');
-        jnode.val(_('pad.userlist.unnamed'));
+        jnode.val(html10n.get('pad.userlist.unnamed'));
       } else {
         jnode.attr('disabled', 'disabled');
         pad.suggestUserName(userId, newName);
       }
     });
-  }
+  };
 
-  function findExistingIndex(userId) {
+  const findExistingIndex = (userId) => {
     let existingIndex = -1;
     for (let i = 0; i < otherUsersInfo.length; i++) {
-      if (otherUsersInfo[i].userId == userId) {
+      if (otherUsersInfo[i].userId === userId) {
         existingIndex = i;
         break;
       }
     }
     return existingIndex;
-  }
+  };
 
-  function setUpEditable(jqueryNode, valueGetter, valueSetter) {
+  const setUpEditable = (jqueryNode, valueGetter, valueSetter) => {
     jqueryNode.bind('focus', (evt) => {
       const oldValue = valueGetter();
       if (jqueryNode.val() !== oldValue) {
@@ -350,16 +349,18 @@ const paduserlist = (function () {
       jqueryNode.val(valueGetter()).blur();
     });
     jqueryNode.removeAttr('disabled').addClass('editable');
-  }
+  };
 
-  var pad = undefined;
-  var self = {
+  let pad = undefined;
+  const self = {
     init(myInitialUserInfo, _pad) {
       pad = _pad;
 
       self.setMyUserInfo(myInitialUserInfo);
 
-      if ($('#online_count').length === 0) $('#editbar [data-key=showusers] > a').append('<span id="online_count">1</span>');
+      if ($('#online_count').length === 0) {
+        $('#editbar [data-key=showusers] > a').append('<span id="online_count">1</span>');
+      }
 
       $('#otheruserstable tr').remove();
 
@@ -388,23 +389,24 @@ const paduserlist = (function () {
       });
       //
     },
-    usersOnline() {
+    usersOnline: () => {
       // Returns an object of users who are currently online on this pad
-      const userList = [].concat(otherUsersInfo); // Make a copy of the otherUsersInfo, otherwise every call to users modifies the referenced array
+      // Make a copy of the otherUsersInfo, otherwise every call to users
+      // modifies the referenced array
+      const userList = [].concat(otherUsersInfo);
       // Now we need to add ourselves..
       userList.push(myUserInfo);
       return userList;
     },
-    users() {
+    users: () => {
       // Returns an object of users who have been on this pad
       const userList = self.usersOnline();
 
       // Now we add historical authors
       const historical = clientVars.collab_client_vars.historicalAuthorData;
-      for (const key in historical) {
-        var userId = historical[key].userId;
+      for (const [key, {userId}] of Object.entries(historical)) {
         // Check we don't already have this author in our array
-        var exists = false;
+        let exists = false;
 
         userList.forEach((user) => {
           if (user.userId === userId) exists = true;
@@ -416,7 +418,7 @@ const paduserlist = (function () {
       }
       return userList;
     },
-    setMyUserInfo(info) {
+    setMyUserInfo: (info) => {
       // translate the colorId
       if (typeof info.colorId === 'number') {
         info.colorId = clientVars.colorPalette[info.colorId];
@@ -427,8 +429,8 @@ const paduserlist = (function () {
 
       self.renderMyUserInfo();
     },
-    userJoinOrUpdate(info) {
-      if ((!info.userId) || (info.userId == myUserInfo.userId)) {
+    userJoinOrUpdate: (info) => {
+      if ((!info.userId) || (info.userId === myUserInfo.userId)) {
         // not sure how this would happen
         return;
       }
@@ -438,7 +440,8 @@ const paduserlist = (function () {
       });
 
       const userData = {};
-      userData.color = typeof info.colorId === 'number' ? clientVars.colorPalette[info.colorId] : info.colorId;
+      userData.color = typeof info.colorId === 'number'
+        ? clientVars.colorPalette[info.colorId] : info.colorId;
       userData.name = info.name;
       userData.status = '';
       userData.activity = '';
@@ -460,12 +463,12 @@ const paduserlist = (function () {
         const nameThis = (info.name || '').toLowerCase();
         const idN = infoN.userId;
         const idThis = info.userId;
-        return (nameN > nameThis) || (nameN == nameThis && idN > idThis);
+        return (nameN > nameThis) || (nameN === nameThis && idN > idThis);
       });
 
       if (existingIndex >= 0) {
         // update
-        if (existingIndex == newIndex) {
+        if (existingIndex === newIndex) {
           otherUsersInfo[existingIndex] = info;
           otherUsersData[existingIndex] = userData;
           rowManager.updateRow(existingIndex, userData);
@@ -485,10 +488,10 @@ const paduserlist = (function () {
 
       self.updateNumberOfOnlineUsers();
     },
-    updateNumberOfOnlineUsers() {
+    updateNumberOfOnlineUsers: () => {
       let online = 1; // you are always online!
       for (let i = 0; i < otherUsersData.length; i++) {
-        if (otherUsersData[i].status == '') {
+        if (otherUsersData[i].status === '') {
           online++;
         }
       }
@@ -497,7 +500,7 @@ const paduserlist = (function () {
 
       return online;
     },
-    userLeave(info) {
+    userLeave: (info) => {
       const existingIndex = findExistingIndex(info.userId);
       if (existingIndex >= 0) {
         const userData = otherUsersData[existingIndex];
@@ -510,11 +513,12 @@ const paduserlist = (function () {
         // joins, or updates happen for this user in the
         // next N seconds, to remove the user from the list.
         const thisUserId = info.userId;
-        var thisLeaveTimer = window.setTimeout(() => {
+        const thisLeaveTimer = window.setTimeout(() => {
           const newExistingIndex = findExistingIndex(thisUserId);
           if (newExistingIndex >= 0) {
             const newUserData = otherUsersData[newExistingIndex];
-            if (newUserData.status == 'Disconnected' && newUserData.leaveTimer == thisLeaveTimer) {
+            if (newUserData.status === 'Disconnected' &&
+                newUserData.leaveTimer === thisLeaveTimer) {
               otherUsersInfo.splice(newExistingIndex, 1);
               otherUsersData.splice(newExistingIndex, 1);
               rowManager.removeRow(newExistingIndex);
@@ -529,7 +533,7 @@ const paduserlist = (function () {
 
       self.updateNumberOfOnlineUsers();
     },
-    renderMyUserInfo() {
+    renderMyUserInfo: () => {
       if (myUserInfo.name) {
         $('#myusernameedit').removeClass('editempty').val(myUserInfo.name);
       } else {
@@ -549,23 +553,20 @@ const paduserlist = (function () {
   return self;
 }());
 
-function getColorPickerSwatchIndex(jnode) {
-  //  return Number(jnode.get(0).className.match(/\bn([0-9]+)\b/)[1])-1;
-  return $('#colorpickerswatches li').index(jnode);
-}
+const getColorPickerSwatchIndex = (jnode) => $('#colorpickerswatches li').index(jnode);
 
-function closeColorPicker(accept) {
+const closeColorPicker = (accept) => {
   if (accept) {
-    var newColor = $('#mycolorpickerpreview').css('background-color');
+    let newColor = $('#mycolorpickerpreview').css('background-color');
     const parts = newColor.match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/);
     // parts now should be ["rgb(0, 70, 255", "0", "70", "255"]
     if (parts) {
       delete (parts[0]);
       for (let i = 1; i <= 3; ++i) {
         parts[i] = parseInt(parts[i]).toString(16);
-        if (parts[i].length == 1) parts[i] = `0${parts[i]}`;
+        if (parts[i].length === 1) parts[i] = `0${parts[i]}`;
       }
-      var newColor = `#${parts.join('')}`; // "0070ff"
+      newColor = `#${parts.join('')}`; // "0070ff"
     }
     myUserInfo.colorId = newColor;
     pad.notifyChangeColor(newColor);
@@ -577,10 +578,9 @@ function closeColorPicker(accept) {
 
   colorPickerOpen = false;
   $('#mycolorpicker').removeClass('popup-show');
-}
+};
 
-function showColorPicker() {
-  previousColorId = myUserInfo.colorId;
+const showColorPicker = () => {
   $.farbtastic('#colorpicker').setColor(myUserInfo.colorId);
 
   if (!colorPickerOpen) {
@@ -613,6 +613,6 @@ function showColorPicker() {
     $('#colorpickerswatches li').removeClass('picked');
     $($('#colorpickerswatches li')[myUserInfo.colorId]).addClass('picked'); // seems weird
   }
-}
+};
 
 exports.paduserlist = paduserlist;
diff --git a/src/static/js/pad_utils.js b/src/static/js/pad_utils.js
index 676029650..8cc6efb1a 100644
--- a/src/static/js/pad_utils.js
+++ b/src/static/js/pad_utils.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
@@ -20,8 +22,6 @@
  * limitations under the License.
  */
 
-'use strict';
-
 const Security = require('./security');
 
 /**