diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index bbc755ad3..a5e4f96ae 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -291,6 +291,9 @@ importers:
       '@types/jquery':
         specifier: ^3.5.30
         version: 3.5.30
+      '@types/js-cookie':
+        specifier: ^3.0.6
+        version: 3.0.6
       '@types/jsdom':
         specifier: ^21.1.7
         version: 21.1.7
@@ -1501,6 +1504,9 @@ packages:
   '@types/jquery@3.5.30':
     resolution: {integrity: sha512-nbWKkkyb919DOUxjmRVk8vwtDb0/k8FKncmUKFi+NY+QXqWltooxTrswvz4LspQwxvLdvzBN1TImr6cw3aQx2A==}
 
+  '@types/js-cookie@3.0.6':
+    resolution: {integrity: sha512-wkw9yd1kEXOPnvEeEV1Go1MmxtBJL0RR79aOTAApecWFVu7w0NNXNqhcWgvw2YgZDYadliXkl14pa3WXw5jlCQ==}
+
   '@types/jsdom@21.1.7':
     resolution: {integrity: sha512-yOriVnggzrnQ3a9OKOCxaVuSug3w3/SbOj5i7VwXWZEyUNl3bLF9V3MfxGbZKuwqJOQyRfqXyROBB1CoZLFWzA==}
 
@@ -5685,6 +5691,8 @@ snapshots:
     dependencies:
       '@types/sizzle': 2.3.8
 
+  '@types/js-cookie@3.0.6': {}
+
   '@types/jsdom@21.1.7':
     dependencies:
       '@types/node': 22.4.0
diff --git a/src/node/db/API.ts b/src/node/db/API.ts
index 9ce84fc51..e9f445560 100644
--- a/src/node/db/API.ts
+++ b/src/node/db/API.ts
@@ -20,7 +20,7 @@
  */
 
 const Changeset = require('../../static/js/Changeset');
-const ChatMessage = require('../../static/js/ChatMessage');
+import ChatMessage from '../../static/js/ChatMessage';
 const CustomError = require('../utils/customError');
 const padManager = require('./PadManager');
 const padMessageHandler = require('../handler/PadMessageHandler');
diff --git a/src/node/db/AuthorManager.ts b/src/node/db/AuthorManager.ts
index 2f4e7d751..4bcfa2c0d 100644
--- a/src/node/db/AuthorManager.ts
+++ b/src/node/db/AuthorManager.ts
@@ -21,8 +21,8 @@
 
 const db = require('./DB');
 const CustomError = require('../utils/customError');
-const hooks = require('../../static/js/pluginfw/hooks.js');
-const {randomString, padutils: {warnDeprecated}} = require('../../static/js/pad_utils');
+const hooks = require('../../static/js/pluginfw/hooks');
+import padutils, {randomString} from "../../static/js/pad_utils";
 
 exports.getColorPalette = () => [
   '#ffc7c7',
@@ -169,7 +169,7 @@ exports.getAuthorId = async (token: string, user: object) => {
  * @param {String} token The token
  */
 exports.getAuthor4Token = async (token: string) => {
-  warnDeprecated(
+  padutils.warnDeprecated(
       'AuthorManager.getAuthor4Token() is deprecated; use AuthorManager.getAuthorId() instead');
   return await getAuthor4Token(token);
 };
diff --git a/src/node/db/GroupManager.ts b/src/node/db/GroupManager.ts
index 0524c4eda..b8cb6db02 100644
--- a/src/node/db/GroupManager.ts
+++ b/src/node/db/GroupManager.ts
@@ -20,7 +20,7 @@
  */
 
 const CustomError = require('../utils/customError');
-const randomString = require('../../static/js/pad_utils').randomString;
+import {randomString} from "../../static/js/pad_utils";
 const db = require('./DB');
 const padManager = require('./PadManager');
 const sessionManager = require('./SessionManager');
diff --git a/src/node/db/Pad.ts b/src/node/db/Pad.ts
index fa4af994d..e117bb343 100644
--- a/src/node/db/Pad.ts
+++ b/src/node/db/Pad.ts
@@ -7,10 +7,10 @@ import {MapArrayType} from "../types/MapType";
  * The pad object, defined with joose
  */
 
-const AttributeMap = require('../../static/js/AttributeMap');
+import AttributeMap from '../../static/js/AttributeMap';
 const Changeset = require('../../static/js/Changeset');
-const ChatMessage = require('../../static/js/ChatMessage');
-const AttributePool = require('../../static/js/AttributePool');
+import ChatMessage from '../../static/js/ChatMessage';
+import AttributePool from '../../static/js/AttributePool';
 const Stream = require('../utils/Stream');
 const assert = require('assert').strict;
 const db = require('./DB');
@@ -23,7 +23,7 @@ const CustomError = require('../utils/customError');
 const readOnlyManager = require('./ReadOnlyManager');
 const randomString = require('../utils/randomstring');
 const hooks = require('../../static/js/pluginfw/hooks');
-const {padutils: {warnDeprecated}} = require('../../static/js/pad_utils');
+import pad_utils from "../../static/js/pad_utils";
 const promises = require('../utils/promises');
 
 /**
@@ -40,7 +40,7 @@ exports.cleanText = (txt:string): string => txt.replace(/\r\n/g, '\n')
 class Pad {
   private db: Database;
   private atext: AText;
-  private pool: APool;
+  private pool: AttributePool;
   private head: number;
     private chatHead: number;
     private publicStatus: boolean;
@@ -126,11 +126,11 @@ class Pad {
         pad: this,
         authorId,
         get author() {
-          warnDeprecated(`${hook} hook author context is deprecated; use authorId instead`);
+          pad_utils.warnDeprecated(`${hook} hook author context is deprecated; use authorId instead`);
           return this.authorId;
         },
         set author(authorId) {
-          warnDeprecated(`${hook} hook author context is deprecated; use authorId instead`);
+          pad_utils.warnDeprecated(`${hook} hook author context is deprecated; use authorId instead`);
           this.authorId = authorId;
         },
         ...this.head === 0 ? {} : {
@@ -330,7 +330,7 @@ class Pad {
    * @param {?number} [time] - Message timestamp (milliseconds since epoch). Deprecated; use
    *     `msgOrText.time` instead.
    */
-  async appendChatMessage(msgOrText: string|typeof ChatMessage, authorId = null, time = null) {
+  async appendChatMessage(msgOrText: string| ChatMessage, authorId = null, time = null) {
     const msg =
           msgOrText instanceof ChatMessage ? msgOrText : new ChatMessage(msgOrText, authorId, time);
     this.chatHead++;
@@ -437,11 +437,11 @@ class Pad {
     // let the plugins know the pad was copied
     await hooks.aCallAll('padCopy', {
       get originalPad() {
-        warnDeprecated('padCopy originalPad context property is deprecated; use srcPad instead');
+        pad_utils.warnDeprecated('padCopy originalPad context property is deprecated; use srcPad instead');
         return this.srcPad;
       },
       get destinationID() {
-        warnDeprecated(
+        pad_utils.warnDeprecated(
             'padCopy destinationID context property is deprecated; use dstPad.id instead');
         return this.dstPad.id;
       },
@@ -538,11 +538,11 @@ class Pad {
 
     await hooks.aCallAll('padCopy', {
       get originalPad() {
-        warnDeprecated('padCopy originalPad context property is deprecated; use srcPad instead');
+        pad_utils.warnDeprecated('padCopy originalPad context property is deprecated; use srcPad instead');
         return this.srcPad;
       },
       get destinationID() {
-        warnDeprecated(
+        pad_utils.warnDeprecated(
             'padCopy destinationID context property is deprecated; use dstPad.id instead');
         return this.dstPad.id;
       },
@@ -603,7 +603,7 @@ class Pad {
     p.push(padManager.removePad(padID));
     p.push(hooks.aCallAll('padRemove', {
       get padID() {
-        warnDeprecated('padRemove padID context property is deprecated; use pad.id instead');
+        pad_utils.warnDeprecated('padRemove padID context property is deprecated; use pad.id instead');
         return this.pad.id;
       },
       pad: this,
diff --git a/src/node/db/SecurityManager.ts b/src/node/db/SecurityManager.ts
index 326bf3659..c2f209a01 100644
--- a/src/node/db/SecurityManager.ts
+++ b/src/node/db/SecurityManager.ts
@@ -22,7 +22,7 @@
 import {UserSettingsObject} from "../types/UserSettingsObject";
 
 const authorManager = require('./AuthorManager');
-const hooks = require('../../static/js/pluginfw/hooks.js');
+const hooks = require('../../static/js/pluginfw/hooks');
 const padManager = require('./PadManager');
 const readOnlyManager = require('./ReadOnlyManager');
 const sessionManager = require('./SessionManager');
@@ -30,7 +30,7 @@ const settings = require('../utils/Settings');
 const webaccess = require('../hooks/express/webaccess');
 const log4js = require('log4js');
 const authLogger = log4js.getLogger('auth');
-const {padutils} = require('../../static/js/pad_utils');
+import padutils from '../../static/js/pad_utils'
 
 const DENY = Object.freeze({accessStatus: 'deny'});
 
diff --git a/src/node/eejs/index.ts b/src/node/eejs/index.ts
index b7f2cf998..5d57e4751 100644
--- a/src/node/eejs/index.ts
+++ b/src/node/eejs/index.ts
@@ -22,7 +22,7 @@
 
 const ejs = require('ejs');
 const fs = require('fs');
-const hooks = require('../../static/js/pluginfw/hooks.js');
+const hooks = require('../../static/js/pluginfw/hooks');
 const path = require('path');
 const resolve = require('resolve');
 const settings = require('../utils/Settings');
diff --git a/src/node/handler/ImportHandler.ts b/src/node/handler/ImportHandler.ts
index 330a2d6f9..286b4fb56 100644
--- a/src/node/handler/ImportHandler.ts
+++ b/src/node/handler/ImportHandler.ts
@@ -31,7 +31,7 @@ import os from 'os';
 const importHtml = require('../utils/ImportHtml');
 const importEtherpad = require('../utils/ImportEtherpad');
 import log4js from 'log4js';
-const hooks = require('../../static/js/pluginfw/hooks.js');
+const hooks = require('../../static/js/pluginfw/hooks');
 
 const logger = log4js.getLogger('ImportHandler');
 
diff --git a/src/node/handler/PadMessageHandler.ts b/src/node/handler/PadMessageHandler.ts
index 390949607..2976381bb 100644
--- a/src/node/handler/PadMessageHandler.ts
+++ b/src/node/handler/PadMessageHandler.ts
@@ -21,28 +21,29 @@
 
 import {MapArrayType} from "../types/MapType";
 
-const AttributeMap = require('../../static/js/AttributeMap');
+import AttributeMap from '../../static/js/AttributeMap';
 const padManager = require('../db/PadManager');
 const Changeset = require('../../static/js/Changeset');
-const ChatMessage = require('../../static/js/ChatMessage');
-const AttributePool = require('../../static/js/AttributePool');
+import ChatMessage from '../../static/js/ChatMessage';
+import AttributePool from '../../static/js/AttributePool';
 const AttributeManager = require('../../static/js/AttributeManager');
 const authorManager = require('../db/AuthorManager');
-const {padutils} = require('../../static/js/pad_utils');
+import padutils from '../../static/js/pad_utils';
 const readOnlyManager = require('../db/ReadOnlyManager');
 const settings = require('../utils/Settings');
 const securityManager = require('../db/SecurityManager');
-const plugins = require('../../static/js/pluginfw/plugin_defs.js');
+const plugins = require('../../static/js/pluginfw/plugin_defs');
 import log4js from 'log4js';
 const messageLogger = log4js.getLogger('message');
 const accessLogger = log4js.getLogger('access');
-const hooks = require('../../static/js/pluginfw/hooks.js');
+const hooks = require('../../static/js/pluginfw/hooks');
 const stats = require('../stats')
 const assert = require('assert').strict;
 import {RateLimiterMemory} from 'rate-limiter-flexible';
 import {ChangesetRequest, PadUserInfo, SocketClientRequest} from "../types/SocketClientRequest";
 import {APool, AText, PadAuthor, PadType} from "../types/PadType";
 import {ChangeSet} from "../types/ChangeSet";
+import {ChatMessageMessage, ClientReadyMessage, ClientSaveRevisionMessage, ClientSuggestUserName, ClientUserChangesMessage, ClientVarMessage, CustomMessage, UserNewInfoMessage} from "../../static/js/types/SocketIOMessage";
 const webaccess = require('../hooks/express/webaccess');
 const { checkValidRev } = require('../utils/checkValidRev');
 
@@ -214,7 +215,7 @@ exports.handleDisconnect = async (socket:any) => {
  * @param socket the socket.io Socket object for the client
  * @param message the message from the client
  */
-exports.handleMessage = async (socket:any, message:typeof ChatMessage) => {
+exports.handleMessage = async (socket:any, message: ClientVarMessage) => {
   const env = process.env.NODE_ENV || 'development';
 
   if (env === 'production') {
@@ -348,15 +349,15 @@ exports.handleMessage = async (socket:any, message:typeof ChatMessage) => {
               stats.counter('pendingEdits').inc();
               await padChannels.enqueue(thisSession.padId, {socket, message});
               break;
-            case 'USERINFO_UPDATE': await handleUserInfoUpdate(socket, message); break;
-            case 'CHAT_MESSAGE': await handleChatMessage(socket, message); break;
+            case 'USERINFO_UPDATE': await handleUserInfoUpdate(socket, message as unknown as UserNewInfoMessage); break;
+            case 'CHAT_MESSAGE': await handleChatMessage(socket, message as unknown as ChatMessageMessage); break;
             case 'GET_CHAT_MESSAGES': await handleGetChatMessages(socket, message); break;
-            case 'SAVE_REVISION': await handleSaveRevisionMessage(socket, message); break;
+            case 'SAVE_REVISION': await handleSaveRevisionMessage(socket, message as unknown as ClientSaveRevisionMessage); break;
             case 'CLIENT_MESSAGE': {
               const {type} = message.data.payload;
               try {
                 switch (type) {
-                  case 'suggestUserName': handleSuggestUserName(socket, message); break;
+                  case 'suggestUserName': handleSuggestUserName(socket, message as unknown as ClientSuggestUserName); break;
                   default: throw new Error('unknown message type');
                 }
               } catch (err) {
@@ -384,7 +385,7 @@ exports.handleMessage = async (socket:any, message:typeof ChatMessage) => {
  * @param socket the socket.io Socket object for the client
  * @param message the message from the client
  */
-const handleSaveRevisionMessage = async (socket:any, message: string) => {
+const handleSaveRevisionMessage = async (socket:any, message: ClientSaveRevisionMessage) => {
   const {padId, author: authorId} = sessioninfos[socket.id];
   const pad = await padManager.getPad(padId, null, authorId);
   await pad.addSavedRevision(pad.head, authorId);
@@ -397,7 +398,7 @@ const handleSaveRevisionMessage = async (socket:any, message: string) => {
  * @param msg {Object} the message we're sending
  * @param sessionID {string} the socketIO session to which we're sending this message
  */
-exports.handleCustomObjectMessage = (msg: typeof ChatMessage, sessionID: string) => {
+exports.handleCustomObjectMessage = (msg: CustomMessage, sessionID: string) => {
   if (msg.data.type === 'CUSTOM') {
     if (sessionID) {
       // a sessionID is targeted: directly to this sessionID
@@ -432,7 +433,7 @@ exports.handleCustomMessage = (padID: string, msgString:string) => {
  * @param socket the socket.io Socket object for the client
  * @param message the message from the client
  */
-const handleChatMessage = async (socket:any, message: typeof ChatMessage) => {
+const handleChatMessage = async (socket:any, message: ChatMessageMessage) => {
   const chatMessage = ChatMessage.fromObject(message.data.message);
   const {padId, author: authorId} = sessioninfos[socket.id];
   // Don't trust the user-supplied values.
@@ -452,7 +453,7 @@ const handleChatMessage = async (socket:any, message: typeof ChatMessage) => {
  * @param {string} [padId] - The destination pad ID. Deprecated; pass a chat message
  *     object as the first argument and the destination pad ID as the second argument instead.
  */
-exports.sendChatMessageToPadClients = async (mt: typeof ChatMessage|number, puId: string, text:string|null = null, padId:string|null = null) => {
+exports.sendChatMessageToPadClients = async (mt: ChatMessage|number, puId: string, text:string|null = null, padId:string|null = null) => {
   const message = mt instanceof ChatMessage ? mt : new ChatMessage(text, puId, mt);
   padId = mt instanceof ChatMessage ? puId : padId;
   const pad = await padManager.getPad(padId, null, message.authorId);
@@ -499,7 +500,7 @@ const handleGetChatMessages = async (socket:any, {data: {start, end}}:any) => {
  * @param socket the socket.io Socket object for the client
  * @param message the message from the client
  */
-const handleSuggestUserName = (socket:any, message: typeof ChatMessage) => {
+const handleSuggestUserName = (socket:any, message: ClientSuggestUserName) => {
   const {newName, unnamedId} = message.data.payload;
   if (newName == null) throw new Error('missing newName');
   if (unnamedId == null) throw new Error('missing unnamedId');
@@ -519,7 +520,7 @@ const handleSuggestUserName = (socket:any, message: typeof ChatMessage) => {
  * @param socket the socket.io Socket object for the client
  * @param message the message from the client
  */
-const handleUserInfoUpdate = async (socket:any, {data: {userInfo: {name, colorId}}}: PadUserInfo) => {
+const handleUserInfoUpdate = async (socket:any, {data: {userInfo: {name, colorId}}}: UserNewInfoMessage) => {
   if (colorId == null) throw new Error('missing colorId');
   if (!name) name = null;
   const session = sessioninfos[socket.id];
@@ -567,7 +568,9 @@ const handleUserInfoUpdate = async (socket:any, {data: {userInfo: {name, colorId
  * @param socket the socket.io Socket object for the client
  * @param message the message from the client
  */
-const handleUserChanges = async (socket:any, message: typeof ChatMessage) => {
+const handleUserChanges = async (socket:any, message: {
+  data: ClientUserChangesMessage
+}) => {
   // This one's no longer pending, as we're gonna process it now
   stats.counter('pendingEdits').dec();
 
@@ -738,7 +741,7 @@ exports.updatePadClients = async (pad: PadType) => {
 /**
  * Copied from the Etherpad Source Code. Don't know what this method does excatly...
  */
-const _correctMarkersInPad = (atext: AText, apool: APool) => {
+const _correctMarkersInPad = (atext: AText, apool: AttributePool) => {
   const text = atext.text;
 
   // collect char positions of line markers (e.g. bullets) in new atext
@@ -785,7 +788,7 @@ const _correctMarkersInPad = (atext: AText, apool: APool) => {
  * @param socket the socket.io Socket object for the client
  * @param message the message from the client
  */
-const handleClientReady = async (socket:any, message: typeof ChatMessage) => {
+const handleClientReady = async (socket:any, message: ClientReadyMessage) => {
   const sessionInfo = sessioninfos[socket.id];
   if (sessionInfo == null) throw new Error('client disconnected');
   assert(sessionInfo.author);
@@ -793,8 +796,9 @@ const handleClientReady = async (socket:any, message: typeof ChatMessage) => {
   await hooks.aCallAll('clientReady', message); // Deprecated due to awkward context.
 
   let {colorId: authorColorId, name: authorName} = message.userInfo || {};
-  if (authorColorId && !/^#(?:[0-9A-F]{3}){1,2}$/i.test(authorColorId)) {
+  if (authorColorId && !/^#(?:[0-9A-F]{3}){1,2}$/i.test(authorColorId as string)) {
     messageLogger.warn(`Ignoring invalid colorId in CLIENT_READY message: ${authorColorId}`);
+    // @ts-ignore
     authorColorId = null;
   }
   await Promise.all([
@@ -872,7 +876,7 @@ const handleClientReady = async (socket:any, message: typeof ChatMessage) => {
     const revisionsNeeded = [];
     const changesets:MapArrayType<any> = {};
 
-    let startNum = message.client_rev + 1;
+    let startNum = message.client_rev! + 1;
     let endNum = pad.getHeadRevisionNumber() + 1;
 
     const headNum = pad.getHeadRevisionNumber();
diff --git a/src/node/hooks/i18n.ts b/src/node/hooks/i18n.ts
index 500f1f887..c4cc58bdd 100644
--- a/src/node/hooks/i18n.ts
+++ b/src/node/hooks/i18n.ts
@@ -7,7 +7,7 @@ const languages = require('languages4translatewiki');
 const fs = require('fs');
 const path = require('path');
 const _ = require('underscore');
-const pluginDefs = require('../../static/js/pluginfw/plugin_defs.js');
+const pluginDefs = require('../../static/js/pluginfw/plugin_defs');
 const existsSync = require('../utils/path_exists');
 const settings = require('../utils/Settings');
 
diff --git a/src/node/utils/ExportHelper.ts b/src/node/utils/ExportHelper.ts
index f3a438e86..e12332b06 100644
--- a/src/node/utils/ExportHelper.ts
+++ b/src/node/utils/ExportHelper.ts
@@ -19,7 +19,8 @@
  * limitations under the License.
  */
 
-const AttributeMap = require('../../static/js/AttributeMap');
+import AttributeMap from '../../static/js/AttributeMap';
+import AttributePool from "../../static/js/AttributePool";
 const Changeset = require('../../static/js/Changeset');
 const { checkValidRev } = require('./checkValidRev');
 
@@ -51,7 +52,7 @@ type LineModel = {
   [id:string]:string|number|LineModel
 }
 
-exports._analyzeLine = (text:string, aline: LineModel, apool: Function) => {
+exports._analyzeLine = (text:string, aline: LineModel, apool: AttributePool) => {
   const line: LineModel = {};
 
   // identify list
diff --git a/src/node/utils/ExportHtml.ts b/src/node/utils/ExportHtml.ts
index 3b84c4380..138f084ba 100644
--- a/src/node/utils/ExportHtml.ts
+++ b/src/node/utils/ExportHtml.ts
@@ -27,7 +27,7 @@ const hooks = require('../../static/js/pluginfw/hooks');
 const eejs = require('../eejs');
 const _analyzeLine = require('./ExportHelper')._analyzeLine;
 const _encodeWhitespace = require('./ExportHelper')._encodeWhitespace;
-const padutils = require('../../static/js/pad_utils').padutils;
+import padutils from "../../static/js/pad_utils";
 
 const getPadHTML = async (pad: PadType, revNum: string) => {
   let atext = pad.atext;
diff --git a/src/node/utils/ImportEtherpad.ts b/src/node/utils/ImportEtherpad.ts
index e75c5fd42..cf34107c7 100644
--- a/src/node/utils/ImportEtherpad.ts
+++ b/src/node/utils/ImportEtherpad.ts
@@ -18,7 +18,7 @@ import {APool} from "../types/PadType";
  * limitations under the License.
  */
 
-const AttributePool = require('../../static/js/AttributePool');
+import AttributePool from '../../static/js/AttributePool';
 const {Pad} = require('../db/Pad');
 const Stream = require('./Stream');
 const authorManager = require('../db/AuthorManager');
@@ -61,7 +61,7 @@ exports.setPadRaw = async (padId: string, r: string, authorId = '') => {
   try {
     const processRecord = async (key:string, value: null|{
       padIDs: string|Record<string, unknown>,
-      pool: APool
+      pool: AttributePool
     }) => {
       if (!value) return;
       const keyParts = key.split(':');
diff --git a/src/node/utils/padDiff.ts b/src/node/utils/padDiff.ts
index d731ebbe4..6074f8bbc 100644
--- a/src/node/utils/padDiff.ts
+++ b/src/node/utils/padDiff.ts
@@ -3,7 +3,7 @@
 import {PadAuthor, PadType} from "../types/PadType";
 import {MapArrayType} from "../types/MapType";
 
-const AttributeMap = require('../../static/js/AttributeMap');
+import AttributeMap from '../../static/js/AttributeMap';
 const Changeset = require('../../static/js/Changeset');
 const attributes = require('../../static/js/attributes');
 const exportHtml = require('./ExportHtml');
diff --git a/src/package.json b/src/package.json
index ce80bd88e..80031af7a 100644
--- a/src/package.json
+++ b/src/package.json
@@ -86,6 +86,7 @@
     "@types/formidable": "^3.4.5",
     "@types/http-errors": "^2.0.4",
     "@types/jquery": "^3.5.30",
+    "@types/js-cookie": "^3.0.6",
     "@types/jsdom": "^21.1.7",
     "@types/jsonwebtoken": "^9.0.6",
     "@types/mime-types": "^2.1.4",
diff --git a/src/static/js/AttributeManager.js b/src/static/js/AttributeManager.ts
similarity index 99%
rename from src/static/js/AttributeManager.js
rename to src/static/js/AttributeManager.ts
index 63af431d9..6a0a545b4 100644
--- a/src/static/js/AttributeManager.js
+++ b/src/static/js/AttributeManager.ts
@@ -1,6 +1,7 @@
+// @ts-nocheck
 'use strict';
 
-const AttributeMap = require('./AttributeMap');
+import AttributeMap from './AttributeMap';
 const Changeset = require('./Changeset');
 const ChangesetUtils = require('./ChangesetUtils');
 const attributes = require('./attributes');
diff --git a/src/static/js/AttributeMap.js b/src/static/js/AttributeMap.ts
similarity index 78%
rename from src/static/js/AttributeMap.js
rename to src/static/js/AttributeMap.ts
index 55640eb8b..07bc106a5 100644
--- a/src/static/js/AttributeMap.js
+++ b/src/static/js/AttributeMap.ts
@@ -1,6 +1,9 @@
 'use strict';
 
-const attributes = require('./attributes');
+import AttributePool from "./AttributePool";
+import {Attribute} from "./types/Attribute";
+
+import attributes from './attributes';
 
 /**
  * A `[key, value]` pair of strings describing a text attribute.
@@ -21,6 +24,7 @@ const attributes = require('./attributes');
  * Convenience class to convert an Op's attribute string to/from a Map of key, value pairs.
  */
 class AttributeMap extends Map {
+  private readonly pool? : AttributePool|null
   /**
    * Converts an attribute string into an AttributeMap.
    *
@@ -28,14 +32,14 @@ class AttributeMap extends Map {
    * @param {AttributePool} pool - Attribute pool.
    * @returns {AttributeMap}
    */
-  static fromString(str, pool) {
+  public static fromString(str: string, pool?: AttributePool|null): AttributeMap {
     return new AttributeMap(pool).updateFromString(str);
   }
 
   /**
    * @param {AttributePool} pool - Attribute pool.
    */
-  constructor(pool) {
+  constructor(pool?: AttributePool|null) {
     super();
     /** @public */
     this.pool = pool;
@@ -46,15 +50,15 @@ class AttributeMap extends Map {
    * @param {string} v - Attribute value.
    * @returns {AttributeMap} `this` (for chaining).
    */
-  set(k, v) {
+  set(k: string, v: string):this {
     k = k == null ? '' : String(k);
     v = v == null ? '' : String(v);
-    this.pool.putAttrib([k, v]);
+    this.pool!.putAttrib([k, v]);
     return super.set(k, v);
   }
 
   toString() {
-    return attributes.attribsToString(attributes.sort([...this]), this.pool);
+    return attributes.attribsToString(attributes.sort([...this]), this.pool!);
   }
 
   /**
@@ -63,7 +67,7 @@ class AttributeMap extends Map {
    *     key is removed from this map (if present).
    * @returns {AttributeMap} `this` (for chaining).
    */
-  update(entries, emptyValueIsDelete = false) {
+  update(entries: Iterable<Attribute>, emptyValueIsDelete: boolean = false): AttributeMap {
     for (let [k, v] of entries) {
       k = k == null ? '' : String(k);
       v = v == null ? '' : String(v);
@@ -83,9 +87,9 @@ class AttributeMap extends Map {
    *     key is removed from this map (if present).
    * @returns {AttributeMap} `this` (for chaining).
    */
-  updateFromString(str, emptyValueIsDelete = false) {
-    return this.update(attributes.attribsFromString(str, this.pool), emptyValueIsDelete);
+  updateFromString(str: string, emptyValueIsDelete: boolean = false): AttributeMap {
+    return this.update(attributes.attribsFromString(str, this.pool!), emptyValueIsDelete);
   }
 }
 
-module.exports = AttributeMap;
+export default AttributeMap
diff --git a/src/static/js/AttributePool.js b/src/static/js/AttributePool.ts
similarity index 91%
rename from src/static/js/AttributePool.js
rename to src/static/js/AttributePool.ts
index ccdd2eb35..5bbe52122 100644
--- a/src/static/js/AttributePool.js
+++ b/src/static/js/AttributePool.ts
@@ -44,6 +44,8 @@
  * @property {number} nextNum - The attribute ID to assign to the next new attribute.
  */
 
+import {Attribute} from "./types/Attribute";
+
 /**
  * Represents an attribute pool, which is a collection of attributes (pairs of key and value
  * strings) along with their identifiers (non-negative integers).
@@ -55,6 +57,14 @@
  * in the pad.
  */
 class AttributePool {
+  numToAttrib: {
+    [key: number]: [string, string]
+  }
+  private attribToNum: {
+    [key: number]: [string, string]
+  }
+  private nextNum: number
+
   constructor() {
     /**
      * Maps an attribute identifier to the attribute's `[key, value]` string pair.
@@ -96,7 +106,10 @@ class AttributePool {
    */
   clone() {
     const c = new AttributePool();
-    for (const [n, a] of Object.entries(this.numToAttrib)) c.numToAttrib[n] = [a[0], a[1]];
+    for (const [n, a] of Object.entries(this.numToAttrib)){
+      // @ts-ignore
+      c.numToAttrib[n] = [a[0], a[1]];
+    }
     Object.assign(c.attribToNum, this.attribToNum);
     c.nextNum = this.nextNum;
     return c;
@@ -111,15 +124,17 @@ class AttributePool {
    *     membership in the pool without mutating the pool.
    * @returns {number} The attribute's identifier, or -1 if the attribute is not in the pool.
    */
-  putAttrib(attrib, dontAddIfAbsent = false) {
+  putAttrib(attrib: Attribute, dontAddIfAbsent = false) {
     const str = String(attrib);
     if (str in this.attribToNum) {
+      // @ts-ignore
       return this.attribToNum[str];
     }
     if (dontAddIfAbsent) {
       return -1;
     }
     const num = this.nextNum++;
+    // @ts-ignore
     this.attribToNum[str] = num;
     this.numToAttrib[num] = [String(attrib[0] || ''), String(attrib[1] || '')];
     return num;
@@ -130,7 +145,7 @@ class AttributePool {
    * @returns {Attribute} The attribute with the given identifier, or nullish if there is no such
    *     attribute.
    */
-  getAttrib(num) {
+  getAttrib(num: number): Attribute {
     const pair = this.numToAttrib[num];
     if (!pair) {
       return pair;
@@ -143,7 +158,7 @@ class AttributePool {
    * @returns {string} Eqivalent to `getAttrib(num)[0]` if the attribute exists, otherwise the empty
    *     string.
    */
-  getAttribKey(num) {
+  getAttribKey(num: number): string {
     const pair = this.numToAttrib[num];
     if (!pair) return '';
     return pair[0];
@@ -154,7 +169,7 @@ class AttributePool {
    * @returns {string} Eqivalent to `getAttrib(num)[1]` if the attribute exists, otherwise the empty
    *     string.
    */
-  getAttribValue(num) {
+  getAttribValue(num: number) {
     const pair = this.numToAttrib[num];
     if (!pair) return '';
     return pair[1];
@@ -166,8 +181,8 @@ class AttributePool {
    * @param {Function} func - Callback to call with two arguments: key and value. Its return value
    *     is ignored.
    */
-  eachAttrib(func) {
-    for (const n of Object.keys(this.numToAttrib)) {
+  eachAttrib(func: (k: string, v: string)=>void) {
+    for (const n in this.numToAttrib) {
       const pair = this.numToAttrib[n];
       func(pair[0], pair[1]);
     }
@@ -196,11 +211,12 @@ class AttributePool {
    *     `new AttributePool().fromJsonable(pool.toJsonable())` to copy because the resulting shared
    *     state will lead to pool corruption.
    */
-  fromJsonable(obj) {
+  fromJsonable(obj: this) {
     this.numToAttrib = obj.numToAttrib;
     this.nextNum = obj.nextNum;
     this.attribToNum = {};
     for (const n of Object.keys(this.numToAttrib)) {
+      // @ts-ignore
       this.attribToNum[String(this.numToAttrib[n])] = Number(n);
     }
     return this;
@@ -213,6 +229,7 @@ class AttributePool {
     if (!Number.isInteger(this.nextNum)) throw new Error('nextNum property is not an integer');
     if (this.nextNum < 0) throw new Error('nextNum property is negative');
     for (const prop of ['numToAttrib', 'attribToNum']) {
+      // @ts-ignore
       const obj = this[prop];
       if (obj == null) throw new Error(`${prop} property is null`);
       if (typeof obj !== 'object') throw new TypeError(`${prop} property is not an object`);
@@ -231,9 +248,10 @@ class AttributePool {
       if (v == null) throw new TypeError(`attrib ${i} value is null`);
       if (typeof v !== 'string') throw new TypeError(`attrib ${i} value is not a string`);
       const attrStr = String(attr);
+      // @ts-ignore
       if (this.attribToNum[attrStr] !== i) throw new Error(`attribToNum for ${attrStr} !== ${i}`);
     }
   }
 }
 
-module.exports = AttributePool;
+export default AttributePool
diff --git a/src/static/js/Changeset.js b/src/static/js/Changeset.ts
similarity index 99%
rename from src/static/js/Changeset.js
rename to src/static/js/Changeset.ts
index 53b3f2c8f..99987f8a8 100644
--- a/src/static/js/Changeset.js
+++ b/src/static/js/Changeset.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /*
@@ -22,10 +23,10 @@
  * https://github.com/ether/pad/blob/master/infrastructure/ace/www/easysync2.js
  */
 
-const AttributeMap = require('./AttributeMap');
-const AttributePool = require('./AttributePool');
+import AttributeMap from './AttributeMap';
+import AttributePool from './AttributePool';
 const attributes = require('./attributes');
-const {padutils} = require('./pad_utils');
+import padutils from './pad_utils';
 
 /**
  * A `[key, value]` pair of strings describing a text attribute.
diff --git a/src/static/js/ChangesetUtils.js b/src/static/js/ChangesetUtils.ts
similarity index 99%
rename from src/static/js/ChangesetUtils.js
rename to src/static/js/ChangesetUtils.ts
index ef2be2ebe..b42a7e8f9 100644
--- a/src/static/js/ChangesetUtils.js
+++ b/src/static/js/ChangesetUtils.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/ChatMessage.js b/src/static/js/ChatMessage.ts
similarity index 66%
rename from src/static/js/ChatMessage.js
rename to src/static/js/ChatMessage.ts
index a627f88f9..db2d3403a 100644
--- a/src/static/js/ChatMessage.js
+++ b/src/static/js/ChatMessage.ts
@@ -1,6 +1,6 @@
 'use strict';
 
-const {padutils: {warnDeprecated}} = require('./pad_utils');
+import padUtils from './pad_utils'
 
 /**
  * Represents a chat message stored in the database and transmitted among users. Plugins can extend
@@ -8,14 +8,25 @@ const {padutils: {warnDeprecated}} = require('./pad_utils');
  *
  * Supports serialization to JSON.
  */
-class ChatMessage {
-  static fromObject(obj) {
+export class ChatMessage {
+  customMetadata: any
+  text: string|null
+  public authorId: string|null
+  displayName: string|null
+  time: number|null
+  static fromObject(obj: ChatMessage) {
     // The userId property was renamed to authorId, and userName was renamed to displayName. Accept
     // the old names in case the db record was written by an older version of Etherpad.
     obj = Object.assign({}, obj); // Don't mutate the caller's object.
-    if ('userId' in obj && !('authorId' in obj)) obj.authorId = obj.userId;
+    if ('userId' in obj && !('authorId' in obj)) { // @ts-ignore
+      obj.authorId = obj.userId;
+    }
+    // @ts-ignore
     delete obj.userId;
-    if ('userName' in obj && !('displayName' in obj)) obj.displayName = obj.userName;
+    if ('userName' in obj && !('displayName' in obj)) { // @ts-ignore
+      obj.displayName = obj.userName;
+    }
+    // @ts-ignore
     delete obj.userName;
     return Object.assign(new ChatMessage(), obj);
   }
@@ -25,7 +36,7 @@ class ChatMessage {
    * @param {?string} [authorId] - Initial value of the `authorId` property.
    * @param {?number} [time] - Initial value of the `time` property.
    */
-  constructor(text = null, authorId = null, time = null) {
+  constructor(text: string | null = null, authorId: string | null = null, time: number | null = null) {
     /**
      * The raw text of the user's chat message (before any rendering or processing).
      *
@@ -62,11 +73,11 @@ class ChatMessage {
    * @type {string}
    */
   get userId() {
-    warnDeprecated('ChatMessage.userId property is deprecated; use .authorId instead');
+    padUtils.warnDeprecated('ChatMessage.userId property is deprecated; use .authorId instead');
     return this.authorId;
   }
   set userId(val) {
-    warnDeprecated('ChatMessage.userId property is deprecated; use .authorId instead');
+    padUtils.warnDeprecated('ChatMessage.userId property is deprecated; use .authorId instead');
     this.authorId = val;
   }
 
@@ -77,11 +88,11 @@ class ChatMessage {
    * @type {string}
    */
   get userName() {
-    warnDeprecated('ChatMessage.userName property is deprecated; use .displayName instead');
+    padUtils.warnDeprecated('ChatMessage.userName property is deprecated; use .displayName instead');
     return this.displayName;
   }
   set userName(val) {
-    warnDeprecated('ChatMessage.userName property is deprecated; use .displayName instead');
+    padUtils.warnDeprecated('ChatMessage.userName property is deprecated; use .displayName instead');
     this.displayName = val;
   }
 
@@ -89,10 +100,12 @@ class ChatMessage {
   // doesn't support authorId and displayName.
   toJSON() {
     const {authorId, displayName, ...obj} = this;
+    // @ts-ignore
     obj.userId = authorId;
+    // @ts-ignore
     obj.userName = displayName;
     return obj;
   }
 }
 
-module.exports = ChatMessage;
+export default ChatMessage
diff --git a/src/static/js/ace.js b/src/static/js/ace.ts
similarity index 99%
rename from src/static/js/ace.js
rename to src/static/js/ace.ts
index a1b5d99c8..4c062584c 100644
--- a/src/static/js/ace.js
+++ b/src/static/js/ace.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
diff --git a/src/static/js/ace2_common.js b/src/static/js/ace2_common.ts
similarity index 76%
rename from src/static/js/ace2_common.js
rename to src/static/js/ace2_common.ts
index c1dab5cfd..0a5f308e6 100644
--- a/src/static/js/ace2_common.js
+++ b/src/static/js/ace2_common.ts
@@ -6,6 +6,8 @@
  * TL;DR COMMENTS ON THIS FILE ARE HIGHLY APPRECIATED
  */
 
+import {MapArrayType} from "../../node/types/MapType";
+
 /**
  * Copyright 2009 Google Inc.
  *
@@ -22,11 +24,13 @@
  * limitations under the License.
  */
 
-const isNodeText = (node) => (node.nodeType === 3);
+export const isNodeText = (node: {
+  nodeType: number
+}) => (node.nodeType === 3);
 
-const getAssoc = (obj, name) => obj[`_magicdom_${name}`];
+export const getAssoc = (obj: MapArrayType<any>, name: string) => obj[`_magicdom_${name}`];
 
-const setAssoc = (obj, name, value) => {
+export const setAssoc = (obj: MapArrayType<any>, name: string, value: string) => {
   // note that in IE designMode, properties of a node can get
   // copied to new nodes that are spawned during editing; also,
   // properties representable in HTML text can survive copy-and-paste
@@ -38,7 +42,7 @@ const setAssoc = (obj, name, value) => {
 // between false and true, a number between 0 and numItems inclusive.
 
 
-const binarySearch = (numItems, func) => {
+export const binarySearch = (numItems: number, func: (num: number)=>boolean) => {
   if (numItems < 1) return 0;
   if (func(0)) return 0;
   if (!func(numItems - 1)) return numItems;
@@ -52,17 +56,10 @@ const binarySearch = (numItems, func) => {
   return high;
 };
 
-const binarySearchInfinite = (expectedLength, func) => {
+export const binarySearchInfinite = (expectedLength: number, func: (num: number)=>boolean) => {
   let i = 0;
   while (!func(i)) i += expectedLength;
   return binarySearch(i, func);
 };
 
-const noop = () => {};
-
-exports.isNodeText = isNodeText;
-exports.getAssoc = getAssoc;
-exports.setAssoc = setAssoc;
-exports.binarySearch = binarySearch;
-exports.binarySearchInfinite = binarySearchInfinite;
-exports.noop = noop;
+export const noop = () => {};
diff --git a/src/static/js/ace2_inner.js b/src/static/js/ace2_inner.ts
similarity index 99%
rename from src/static/js/ace2_inner.js
rename to src/static/js/ace2_inner.ts
index 641c5ecdb..af391f115 100644
--- a/src/static/js/ace2_inner.js
+++ b/src/static/js/ace2_inner.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
@@ -18,9 +19,9 @@
  */
 let documentAttributeManager;
 
-const AttributeMap = require('./AttributeMap');
+import AttributeMap from './AttributeMap';
 const browser = require('./vendors/browser');
-const padutils = require('./pad_utils').padutils;
+import padutils from './pad_utils'
 const Ace2Common = require('./ace2_common');
 const $ = require('./rjquery').$;
 
@@ -29,19 +30,18 @@ const getAssoc = Ace2Common.getAssoc;
 const setAssoc = Ace2Common.setAssoc;
 const noop = Ace2Common.noop;
 const hooks = require('./pluginfw/hooks');
-
+import SkipList from "./skiplist";
 import Scroll from './scroll'
+import AttribPool from './AttributePool'
 
 function Ace2Inner(editorInfo, cssManagers) {
   const makeChangesetTracker = require('./changesettracker').makeChangesetTracker;
   const colorutils = require('./colorutils').colorutils;
   const makeContentCollector = require('./contentcollector').makeContentCollector;
   const domline = require('./domline').domline;
-  const AttribPool = require('./AttributePool');
   const Changeset = require('./Changeset');
   const ChangesetUtils = require('./ChangesetUtils');
   const linestylefilter = require('./linestylefilter').linestylefilter;
-  const SkipList = require('./skiplist');
   const undoModule = require('./undomodule').undoModule;
   const AttributeManager = require('./AttributeManager');
   const DEBUG = false;
diff --git a/src/static/js/attributes.js b/src/static/js/attributes.ts
similarity index 77%
rename from src/static/js/attributes.js
rename to src/static/js/attributes.ts
index 4ab347019..b164f8759 100644
--- a/src/static/js/attributes.js
+++ b/src/static/js/attributes.ts
@@ -17,6 +17,9 @@
  * @typedef {string} AttributeString
  */
 
+import AttributePool from "./AttributePool";
+import {Attribute} from "./types/Attribute";
+
 /**
  * Converts an attribute string into a sequence of attribute identifier numbers.
  *
@@ -28,7 +31,7 @@
  *     appear in `str`.
  * @returns {Generator<number>}
  */
-exports.decodeAttribString = function* (str) {
+export const decodeAttribString = function* (str: string): Generator<number> {
   const re = /\*([0-9a-z]+)|./gy;
   let match;
   while ((match = re.exec(str)) != null) {
@@ -38,7 +41,7 @@ exports.decodeAttribString = function* (str) {
   }
 };
 
-const checkAttribNum = (n) => {
+const checkAttribNum = (n: number|object) => {
   if (typeof n !== 'number') throw new TypeError(`not a number: ${n}`);
   if (n < 0) throw new Error(`attribute number is negative: ${n}`);
   if (n !== Math.trunc(n)) throw new Error(`attribute number is not an integer: ${n}`);
@@ -50,7 +53,7 @@ const checkAttribNum = (n) => {
  * @param {Iterable<number>} attribNums - Sequence of attribute numbers.
  * @returns {AttributeString}
  */
-exports.encodeAttribString = (attribNums) => {
+export const encodeAttribString = (attribNums: Iterable<number>): string => {
   let str = '';
   for (const n of attribNums) {
     checkAttribNum(n);
@@ -67,7 +70,7 @@ exports.encodeAttribString = (attribNums) => {
  * @yields {Attribute} The identified attributes, in the same order as `attribNums`.
  * @returns {Generator<Attribute>}
  */
-exports.attribsFromNums = function* (attribNums, pool) {
+export const attribsFromNums = function* (attribNums: Iterable<number>, pool: AttributePool): Generator<Attribute> {
   for (const n of attribNums) {
     checkAttribNum(n);
     const attrib = pool.getAttrib(n);
@@ -87,7 +90,7 @@ exports.attribsFromNums = function* (attribNums, pool) {
  * @yields {number} The attribute number of each attribute in `attribs`, in order.
  * @returns {Generator<number>}
  */
-exports.attribsToNums = function* (attribs, pool) {
+export const attribsToNums = function* (attribs: Iterable<Attribute>, pool: AttributePool) {
   for (const attrib of attribs) yield pool.putAttrib(attrib);
 };
 
@@ -102,8 +105,8 @@ exports.attribsToNums = function* (attribs, pool) {
  * @yields {Attribute} The attributes identified in `str`, in order.
  * @returns {Generator<Attribute>}
  */
-exports.attribsFromString = function* (str, pool) {
-  yield* exports.attribsFromNums(exports.decodeAttribString(str), pool);
+export const attribsFromString = function* (str: string, pool: AttributePool): Generator<Attribute> {
+  yield* attribsFromNums(decodeAttribString(str), pool);
 };
 
 /**
@@ -116,8 +119,8 @@ exports.attribsFromString = function* (str, pool) {
  * @param {AttributePool} pool - Attribute pool.
  * @returns {AttributeString}
  */
-exports.attribsToString =
-    (attribs, pool) => exports.encodeAttribString(exports.attribsToNums(attribs, pool));
+export const attribsToString =
+  (attribs: Iterable<Attribute>, pool: AttributePool): string => encodeAttribString(attribsToNums(attribs, pool));
 
 /**
  * Sorts the attributes in canonical order. The order of entries with the same attribute name is
@@ -126,5 +129,14 @@ exports.attribsToString =
  * @param {Attribute[]} attribs - Attributes to sort in place.
  * @returns {Attribute[]} `attribs` (for chaining).
  */
-exports.sort =
-    (attribs) => attribs.sort(([keyA], [keyB]) => (keyA > keyB ? 1 : 0) - (keyA < keyB ? 1 : 0));
+export const sort = (attribs: Attribute[]): Attribute[] => attribs.sort(([keyA], [keyB]) => (keyA > keyB ? 1 : 0) - (keyA < keyB ? 1 : 0));
+
+export default {
+  decodeAttribString,
+  encodeAttribString,
+  attribsFromNums,
+  attribsToNums,
+  attribsFromString,
+  attribsToString,
+  sort,
+}
diff --git a/src/static/js/basic_error_handler.js b/src/static/js/basic_error_handler.ts
similarity index 99%
rename from src/static/js/basic_error_handler.js
rename to src/static/js/basic_error_handler.ts
index ab400aa8a..ce8c47353 100644
--- a/src/static/js/basic_error_handler.js
+++ b/src/static/js/basic_error_handler.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 // @license magnet:?xt=urn:btih:8e4f440f4c65981c5bf93c76d35135ba5064d8b7&dn=apache-2.0.txt Apache-2.0
 
 /* Copyright 2021 Richard Hansen <rhansen@rhansen.org> */
diff --git a/src/static/js/broadcast.js b/src/static/js/broadcast.ts
similarity index 99%
rename from src/static/js/broadcast.js
rename to src/static/js/broadcast.ts
index 2163fd78e..518107e5a 100644
--- a/src/static/js/broadcast.js
+++ b/src/static/js/broadcast.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
@@ -24,7 +25,7 @@
 
 const makeCSSManager = require('./cssmanager').makeCSSManager;
 const domline = require('./domline').domline;
-const AttribPool = require('./AttributePool');
+import AttribPool from './AttributePool';
 const Changeset = require('./Changeset');
 const attributes = require('./attributes');
 const linestylefilter = require('./linestylefilter').linestylefilter;
diff --git a/src/static/js/broadcast_revisions.js b/src/static/js/broadcast_revisions.ts
similarity index 99%
rename from src/static/js/broadcast_revisions.js
rename to src/static/js/broadcast_revisions.ts
index 8a9eb2e6c..37272d860 100644
--- a/src/static/js/broadcast_revisions.js
+++ b/src/static/js/broadcast_revisions.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/broadcast_slider.js b/src/static/js/broadcast_slider.ts
similarity index 99%
rename from src/static/js/broadcast_slider.js
rename to src/static/js/broadcast_slider.ts
index 848ba06cf..ccd896c4c 100644
--- a/src/static/js/broadcast_slider.js
+++ b/src/static/js/broadcast_slider.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
diff --git a/src/static/js/changesettracker.js b/src/static/js/changesettracker.ts
similarity index 98%
rename from src/static/js/changesettracker.js
rename to src/static/js/changesettracker.ts
index 30c70aa74..86a63546b 100644
--- a/src/static/js/changesettracker.js
+++ b/src/static/js/changesettracker.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
@@ -22,8 +23,8 @@
  * limitations under the License.
  */
 
-const AttributeMap = require('./AttributeMap');
-const AttributePool = require('./AttributePool');
+import AttributeMap from './AttributeMap';
+import AttributePool from './AttributePool';
 const Changeset = require('./Changeset');
 
 const makeChangesetTracker = (scheduler, apool, aceCallbacksProvider) => {
diff --git a/src/static/js/chat.js b/src/static/js/chat.ts
old mode 100755
new mode 100644
similarity index 99%
rename from src/static/js/chat.js
rename to src/static/js/chat.ts
index d32a62c7a..6357663c4
--- a/src/static/js/chat.js
+++ b/src/static/js/chat.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 /**
  * Copyright 2009 Google Inc., 2011 Peter 'Pita' Martischka (Primary Technology Ltd)
@@ -15,8 +16,8 @@
  * limitations under the License.
  */
 
-const ChatMessage = require('./ChatMessage');
-const padutils = require('./pad_utils').padutils;
+import ChatMessage from './ChatMessage';
+import padutils from './pad_utils'
 const padcookie = require('./pad_cookie').padcookie;
 const Tinycon = require('tinycon/tinycon');
 const hooks = require('./pluginfw/hooks');
diff --git a/src/static/js/collab_client.js b/src/static/js/collab_client.ts
similarity index 99%
rename from src/static/js/collab_client.js
rename to src/static/js/collab_client.ts
index 69c8e41f3..7bc1c37df 100644
--- a/src/static/js/collab_client.js
+++ b/src/static/js/collab_client.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/colorutils.js b/src/static/js/colorutils.ts
similarity index 99%
rename from src/static/js/colorutils.js
rename to src/static/js/colorutils.ts
index 9688b8e59..b60b32aa9 100644
--- a/src/static/js/colorutils.js
+++ b/src/static/js/colorutils.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/contentcollector.js b/src/static/js/contentcollector.ts
similarity index 99%
rename from src/static/js/contentcollector.js
rename to src/static/js/contentcollector.ts
index 4735374ee..0c67687e4 100644
--- a/src/static/js/contentcollector.js
+++ b/src/static/js/contentcollector.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
@@ -26,7 +27,7 @@
 
 const _MAX_LIST_LEVEL = 16;
 
-const AttributeMap = require('./AttributeMap');
+import AttributeMap from './AttributeMap';
 const UNorm = require('unorm');
 const Changeset = require('./Changeset');
 const hooks = require('./pluginfw/hooks');
diff --git a/src/static/js/cssmanager.js b/src/static/js/cssmanager.ts
similarity index 99%
rename from src/static/js/cssmanager.js
rename to src/static/js/cssmanager.ts
index 5bf2adb30..89036df67 100644
--- a/src/static/js/cssmanager.js
+++ b/src/static/js/cssmanager.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/domline.js b/src/static/js/domline.ts
similarity index 99%
rename from src/static/js/domline.js
rename to src/static/js/domline.ts
index af786b2dc..900f60176 100644
--- a/src/static/js/domline.js
+++ b/src/static/js/domline.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 // THIS FILE IS ALSO AN APPJET MODULE: etherpad.collab.ace.domline
diff --git a/src/static/js/linestylefilter.js b/src/static/js/linestylefilter.ts
similarity index 99%
rename from src/static/js/linestylefilter.js
rename to src/static/js/linestylefilter.ts
index 632e6b3cc..3caab50f0 100644
--- a/src/static/js/linestylefilter.js
+++ b/src/static/js/linestylefilter.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
@@ -35,7 +36,7 @@ const attributes = require('./attributes');
 const hooks = require('./pluginfw/hooks');
 const linestylefilter = {};
 const AttributeManager = require('./AttributeManager');
-const padutils = require('./pad_utils').padutils;
+import padutils from './pad_utils'
 
 linestylefilter.ATTRIB_CLASSES = {
   bold: 'tag:b',
diff --git a/src/static/js/pad.js b/src/static/js/pad.ts
similarity index 99%
rename from src/static/js/pad.js
rename to src/static/js/pad.ts
index d6648f031..e94611fcd 100644
--- a/src/static/js/pad.js
+++ b/src/static/js/pad.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
@@ -33,7 +34,8 @@ require('./vendors/gritter');
 
 import html10n from './vendors/html10n'
 
-const Cookies = require('./pad_utils').Cookies;
+import {Cookies} from "./pad_utils";
+
 const chat = require('./chat').chat;
 const getCollabClient = require('./collab_client').getCollabClient;
 const padconnectionstatus = require('./pad_connectionstatus').padconnectionstatus;
@@ -44,9 +46,9 @@ const padimpexp = require('./pad_impexp').padimpexp;
 const padmodals = require('./pad_modals').padmodals;
 const padsavedrevs = require('./pad_savedrevs');
 const paduserlist = require('./pad_userlist').paduserlist;
-const padutils = require('./pad_utils').padutils;
+import padutils from './pad_utils'
 const colorutils = require('./colorutils').colorutils;
-const randomString = require('./pad_utils').randomString;
+import {randomString} from "./pad_utils";
 const socketio = require('./socketio');
 
 const hooks = require('./pluginfw/hooks');
diff --git a/src/static/js/pad_automatic_reconnect.js b/src/static/js/pad_automatic_reconnect.ts
similarity index 99%
rename from src/static/js/pad_automatic_reconnect.js
rename to src/static/js/pad_automatic_reconnect.ts
index 03fc91432..8172d5be7 100644
--- a/src/static/js/pad_automatic_reconnect.js
+++ b/src/static/js/pad_automatic_reconnect.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 import html10n from './vendors/html10n';
 
diff --git a/src/static/js/pad_connectionstatus.js b/src/static/js/pad_connectionstatus.ts
similarity index 99%
rename from src/static/js/pad_connectionstatus.js
rename to src/static/js/pad_connectionstatus.ts
index 7b0497d96..600defa8d 100644
--- a/src/static/js/pad_connectionstatus.js
+++ b/src/static/js/pad_connectionstatus.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/pad_cookie.js b/src/static/js/pad_cookie.ts
similarity index 97%
rename from src/static/js/pad_cookie.js
rename to src/static/js/pad_cookie.ts
index 0e946ea5c..bc624e962 100644
--- a/src/static/js/pad_cookie.js
+++ b/src/static/js/pad_cookie.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
@@ -16,7 +17,7 @@
  * limitations under the License.
  */
 
-const Cookies = require('./pad_utils').Cookies;
+import {Cookies} from "./pad_utils";
 
 exports.padcookie = new class {
   constructor() {
diff --git a/src/static/js/pad_editbar.js b/src/static/js/pad_editbar.ts
similarity index 99%
rename from src/static/js/pad_editbar.js
rename to src/static/js/pad_editbar.ts
index af8d59f1f..d98174fe5 100644
--- a/src/static/js/pad_editbar.js
+++ b/src/static/js/pad_editbar.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
@@ -24,7 +25,7 @@
 
 const browser = require('./vendors/browser');
 const hooks = require('./pluginfw/hooks');
-const padutils = require('./pad_utils').padutils;
+import padutils from "./pad_utils";
 const padeditor = require('./pad_editor').padeditor;
 const padsavedrevs = require('./pad_savedrevs');
 const _ = require('underscore');
diff --git a/src/static/js/pad_editor.js b/src/static/js/pad_editor.ts
similarity index 98%
rename from src/static/js/pad_editor.js
rename to src/static/js/pad_editor.ts
index 47a250734..362412f2f 100644
--- a/src/static/js/pad_editor.js
+++ b/src/static/js/pad_editor.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
@@ -21,9 +22,8 @@
  * limitations under the License.
  */
 
-const Cookies = require('./pad_utils').Cookies;
+import padutils,{Cookies} from "./pad_utils";
 const padcookie = require('./pad_cookie').padcookie;
-const padutils = require('./pad_utils').padutils;
 const Ace2Editor = require('./ace').Ace2Editor;
 import html10n from '../js/vendors/html10n'
 
diff --git a/src/static/js/pad_impexp.js b/src/static/js/pad_impexp.ts
similarity index 99%
rename from src/static/js/pad_impexp.js
rename to src/static/js/pad_impexp.ts
index 3aca9fb7c..8b8575c81 100644
--- a/src/static/js/pad_impexp.js
+++ b/src/static/js/pad_impexp.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/pad_modals.js b/src/static/js/pad_modals.ts
similarity index 99%
rename from src/static/js/pad_modals.js
rename to src/static/js/pad_modals.ts
index 54bd83877..3e2c2459b 100644
--- a/src/static/js/pad_modals.js
+++ b/src/static/js/pad_modals.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/pad_savedrevs.js b/src/static/js/pad_savedrevs.ts
similarity index 98%
rename from src/static/js/pad_savedrevs.js
rename to src/static/js/pad_savedrevs.ts
index 4082e0380..6722a03a2 100644
--- a/src/static/js/pad_savedrevs.js
+++ b/src/static/js/pad_savedrevs.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/pad_userlist.js b/src/static/js/pad_userlist.ts
similarity index 99%
rename from src/static/js/pad_userlist.js
rename to src/static/js/pad_userlist.ts
index a0cbd4b44..227e6b063 100644
--- a/src/static/js/pad_userlist.js
+++ b/src/static/js/pad_userlist.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
@@ -16,7 +17,7 @@
  * limitations under the License.
  */
 
-const padutils = require('./pad_utils').padutils;
+import padutils from './pad_utils'
 const hooks = require('./pluginfw/hooks');
 import html10n from './vendors/html10n';
 let myUserInfo = {};
diff --git a/src/static/js/pad_utils.js b/src/static/js/pad_utils.ts
similarity index 58%
rename from src/static/js/pad_utils.js
rename to src/static/js/pad_utils.ts
index 467a8adc9..0a66abf00 100644
--- a/src/static/js/pad_utils.js
+++ b/src/static/js/pad_utils.ts
@@ -6,6 +6,8 @@
  * TL;DR COMMENTS ON THIS FILE ARE HIGHLY APPRECIATED
  */
 
+import {binarySearch} from "./ace2_common";
+
 /**
  * Copyright 2009 Google Inc.
  *
@@ -22,13 +24,14 @@
  * limitations under the License.
  */
 
-const Security = require('./security');
+const Security = require('security');
+import jsCookie, {CookiesStatic} from 'js-cookie'
 
 /**
  * Generates a random String with the given length. Is needed to generate the Author, Group,
  * readonly, session Ids
  */
-const randomString = (len) => {
+export const randomString = (len?: number) => {
   const chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
   let randomstring = '';
   len = len || 20;
@@ -85,13 +88,41 @@ const urlRegex = (() => {
     'tel',
   ].join('|')}):`;
   return new RegExp(
-      `(?:${withAuth}|${withoutAuth}|www\\.)${urlChar}*(?!${postUrlPunct})${urlChar}`, 'g');
+    `(?:${withAuth}|${withoutAuth}|www\\.)${urlChar}*(?!${postUrlPunct})${urlChar}`, 'g');
 })();
 
 // https://stackoverflow.com/a/68957976
 const base64url = /^(?=(?:.{4})*$)[A-Za-z0-9_-]*(?:[AQgw]==|[AEIMQUYcgkosw048]=)?$/;
 
-const padutils = {
+type PadEvent = {
+  which: number
+}
+
+type JQueryNode = JQuery<HTMLElement>
+
+class PadUtils {
+  public urlRegex: RegExp
+  public wordCharRegex: RegExp
+  public warnDeprecatedFlags: {
+    disabledForTestingOnly: boolean,
+    _rl?: {
+      prevs: Map<string, number>,
+      now: () => number,
+      period: number
+    }
+    logger?: any
+  }
+  public globalExceptionHandler: null | any = null;
+
+
+  constructor() {
+    this.warnDeprecatedFlags = {
+      disabledForTestingOnly: false
+    }
+    this.wordCharRegex = wordCharRegex
+    this.urlRegex = urlRegex
+  }
+
   /**
    * Prints a warning message followed by a stack trace (to make it easier to figure out what code
    * is using the deprecated function).
@@ -107,41 +138,41 @@ const padutils = {
    * @param {...*} args - Passed to `padutils.warnDeprecated.logger.warn` (or `console.warn` if no
    *     logger is set), with a stack trace appended if available.
    */
-  warnDeprecated: (...args) => {
-    if (padutils.warnDeprecated.disabledForTestingOnly) return;
+  warnDeprecated = (...args: any[]) => {
+    if (this.warnDeprecatedFlags.disabledForTestingOnly) return;
     const err = new Error();
-    if (Error.captureStackTrace) Error.captureStackTrace(err, padutils.warnDeprecated);
+    if (Error.captureStackTrace) Error.captureStackTrace(err, this.warnDeprecated);
     err.name = '';
     // Rate limit identical deprecation warnings (as determined by the stack) to avoid log spam.
     if (typeof err.stack === 'string') {
-      if (padutils.warnDeprecated._rl == null) {
-        padutils.warnDeprecated._rl =
-            {prevs: new Map(), now: () => Date.now(), period: 10 * 60 * 1000};
+      if (this.warnDeprecatedFlags._rl == null) {
+        this.warnDeprecatedFlags._rl =
+          {prevs: new Map(), now: () => Date.now(), period: 10 * 60 * 1000};
       }
-      const rl = padutils.warnDeprecated._rl;
+      const rl = this.warnDeprecatedFlags._rl;
       const now = rl.now();
       const prev = rl.prevs.get(err.stack);
       if (prev != null && now - prev < rl.period) return;
       rl.prevs.set(err.stack, now);
     }
     if (err.stack) args.push(err.stack);
-    (padutils.warnDeprecated.logger || console).warn(...args);
-  },
-
-  escapeHtml: (x) => Security.escapeHTML(String(x)),
-  uniqueId: () => {
+    (this.warnDeprecatedFlags.logger || console).warn(...args);
+  }
+  escapeHtml = (x: string) => Security.escapeHTML(String(x))
+  uniqueId = () => {
     const pad = require('./pad').pad; // Sidestep circular dependency
     // returns string that is exactly 'width' chars, padding with zeros and taking rightmost digits
     const encodeNum =
-        (n, width) => (Array(width + 1).join('0') + Number(n).toString(35)).slice(-width);
+      (n: number, width: number) => (Array(width + 1).join('0') + Number(n).toString(35)).slice(-width);
     return [
       pad.getClientIp(),
       encodeNum(+new Date(), 7),
       encodeNum(Math.floor(Math.random() * 1e9), 4),
     ].join('.');
-  },
+  }
+
   // e.g. "Thu Jun 18 2009 13:09"
-  simpleDateTime: (date) => {
+  simpleDateTime = (date: string) => {
     const d = new Date(+date); // accept either number or date
     const dayOfWeek = (['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'])[d.getDay()];
     const month = ([
@@ -162,16 +193,14 @@ const padutils = {
     const year = d.getFullYear();
     const hourmin = `${d.getHours()}:${(`0${d.getMinutes()}`).slice(-2)}`;
     return `${dayOfWeek} ${month} ${dayOfMonth} ${year} ${hourmin}`;
-  },
-  wordCharRegex,
-  urlRegex,
+  }
   // returns null if no URLs, or [[startIndex1, url1], [startIndex2, url2], ...]
-  findURLs: (text) => {
+  findURLs = (text: string) => {
     // Copy padutils.urlRegex so that the use of .exec() below (which mutates the RegExp object)
     // does not break other concurrent uses of padutils.urlRegex.
-    const urlRegex = new RegExp(padutils.urlRegex, 'g');
+    const urlRegex = new RegExp(this.urlRegex, 'g');
     urlRegex.lastIndex = 0;
-    let urls = null;
+    let urls: [number, string][] | null = null;
     let execResult;
     // TODO: Switch to String.prototype.matchAll() after support for Node.js < 12.0.0 is dropped.
     while ((execResult = urlRegex.exec(text))) {
@@ -181,18 +210,19 @@ const padutils = {
       urls.push([startIndex, url]);
     }
     return urls;
-  },
-  escapeHtmlWithClickableLinks: (text, target) => {
+  }
+  escapeHtmlWithClickableLinks = (text: string, target: string) => {
     let idx = 0;
     const pieces = [];
-    const urls = padutils.findURLs(text);
+    const urls = this.findURLs(text);
 
-    const advanceTo = (i) => {
-      if (i > idx) {
-        pieces.push(Security.escapeHTML(text.substring(idx, i)));
-        idx = i;
+    const advanceTo = (i: number) => {
+        if (i > idx) {
+          pieces.push(Security.escapeHTML(text.substring(idx, i)));
+          idx = i;
+        }
       }
-    };
+    ;
     if (urls) {
       for (let j = 0; j < urls.length; j++) {
         const startIndex = urls[j][0];
@@ -206,25 +236,25 @@ const padutils = {
         // https://mathiasbynens.github.io/rel-noopener/
         // https://github.com/ether/etherpad-lite/pull/3636
         pieces.push(
-            '<a ',
-            (target ? `target="${Security.escapeHTMLAttribute(target)}" ` : ''),
-            'href="',
-            Security.escapeHTMLAttribute(href),
-            '" rel="noreferrer noopener">');
+          '<a ',
+          (target ? `target="${Security.escapeHTMLAttribute(target)}" ` : ''),
+          'href="',
+          Security.escapeHTMLAttribute(href),
+          '" rel="noreferrer noopener">');
         advanceTo(startIndex + href.length);
         pieces.push('</a>');
       }
     }
     advanceTo(text.length);
     return pieces.join('');
-  },
-  bindEnterAndEscape: (node, onEnter, onEscape) => {
+  }
+  bindEnterAndEscape = (node: JQueryNode, onEnter: Function, onEscape: Function) => {
     // Use keypress instead of keyup in bindEnterAndEscape. Keyup event is fired on enter in IME
     // (Input Method Editor), But keypress is not. So, I changed to use keypress instead of keyup.
     // It is work on Windows (IE8, Chrome 6.0.472), CentOs (Firefox 3.0) and Mac OSX (Firefox
     // 3.6.10, Chrome 6.0.472, Safari 5.0).
     if (onEnter) {
-      node.on('keypress', (evt) => {
+      node.on('keypress', (evt: { which: number; }) => {
         if (evt.which === 13) {
           onEnter(evt);
         }
@@ -238,13 +268,15 @@ const padutils = {
         }
       });
     }
-  },
-  timediff: (d) => {
+  }
+
+  timediff = (d: number) => {
     const pad = require('./pad').pad; // Sidestep circular dependency
-    const format = (n, word) => {
-      n = Math.round(n);
-      return (`${n} ${word}${n !== 1 ? 's' : ''} ago`);
-    };
+    const format = (n: number, word: string) => {
+        n = Math.round(n);
+        return (`${n} ${word}${n !== 1 ? 's' : ''} ago`);
+      }
+    ;
     d = Math.max(0, (+(new Date()) - (+d) - pad.clientTimeOffset) / 1000);
     if (d < 60) {
       return format(d, 'second');
@@ -259,78 +291,89 @@ const padutils = {
     }
     d /= 24;
     return format(d, 'day');
-  },
-  makeAnimationScheduler: (funcToAnimateOneStep, stepTime, stepsAtOnce) => {
-    if (stepsAtOnce === undefined) {
-      stepsAtOnce = 1;
+  }
+  makeAnimationScheduler =
+    (funcToAnimateOneStep: any, stepTime: number, stepsAtOnce?: number) => {
+      if (stepsAtOnce === undefined) {
+        stepsAtOnce = 1;
+      }
+
+      let animationTimer: any = null;
+
+      const scheduleAnimation = () => {
+        if (!animationTimer) {
+          animationTimer = window.setTimeout(() => {
+            animationTimer = null;
+            let n = stepsAtOnce;
+            let moreToDo = true;
+            while (moreToDo && n > 0) {
+              moreToDo = funcToAnimateOneStep();
+              n--;
+            }
+            if (moreToDo) {
+              // more to do
+              scheduleAnimation();
+            }
+          }, stepTime * stepsAtOnce);
+        }
+      };
+      return {scheduleAnimation};
     }
 
-    let animationTimer = null;
+  makeFieldLabeledWhenEmpty
+    =
+    (field: JQueryNode, labelText: string) => {
+      field = $(field);
 
-    const scheduleAnimation = () => {
-      if (!animationTimer) {
-        animationTimer = window.setTimeout(() => {
-          animationTimer = null;
-          let n = stepsAtOnce;
-          let moreToDo = true;
-          while (moreToDo && n > 0) {
-            moreToDo = funcToAnimateOneStep();
-            n--;
-          }
-          if (moreToDo) {
-            // more to do
-            scheduleAnimation();
-          }
-        }, stepTime * stepsAtOnce);
-      }
-    };
-    return {scheduleAnimation};
-  },
-  makeFieldLabeledWhenEmpty: (field, labelText) => {
-    field = $(field);
-
-    const clear = () => {
-      field.addClass('editempty');
-      field.val(labelText);
-    };
-    field.focus(() => {
-      if (field.hasClass('editempty')) {
-        field.val('');
-      }
-      field.removeClass('editempty');
-    });
-    field.on('blur', () => {
-      if (!field.val()) {
-        clear();
-      }
-    });
-    return {
-      clear,
-    };
-  },
-  getCheckbox: (node) => $(node).is(':checked'),
-  setCheckbox: (node, value) => {
-    if (value) {
-      $(node).attr('checked', 'checked');
-    } else {
-      $(node).prop('checked', false);
+      const clear = () => {
+          field.addClass('editempty');
+          field.val(labelText);
+        }
+      ;
+      field.focus(() => {
+        if (field.hasClass('editempty')) {
+          field.val('');
+        }
+        field.removeClass('editempty');
+      });
+      field.on('blur', () => {
+        if (!field.val()) {
+          clear();
+        }
+      });
+      return {
+        clear,
+      };
     }
-  },
-  bindCheckboxChange: (node, func) => {
-    $(node).on('change', func);
-  },
-  encodeUserId: (userId) => userId.replace(/[^a-y0-9]/g, (c) => {
-    if (c === '.') return '-';
-    return `z${c.charCodeAt(0)}z`;
-  }),
-  decodeUserId: (encodedUserId) => encodedUserId.replace(/[a-y0-9]+|-|z.+?z/g, (cc) => {
-    if (cc === '-') { return '.'; } else if (cc.charAt(0) === 'z') {
-      return String.fromCharCode(Number(cc.slice(1, -1)));
-    } else {
-      return cc;
+  getCheckbox = (node: string) => $(node).is(':checked')
+  setCheckbox =
+    (node: JQueryNode, value: boolean) => {
+      if (value) {
+        $(node).attr('checked', 'checked');
+      } else {
+        $(node).prop('checked', false);
+      }
     }
-  }),
-
+  bindCheckboxChange =
+    (node: JQueryNode, func: Function) => {
+      // @ts-ignore
+      $(node).on("change", func);
+    }
+  encodeUserId =
+    (userId: string) => userId.replace(/[^a-y0-9]/g, (c) => {
+      if (c === '.') return '-';
+      return `z${c.charCodeAt(0)}z`;
+    })
+  decodeUserId =
+    (encodedUserId: string) => encodedUserId.replace(/[a-y0-9]+|-|z.+?z/g, (cc) => {
+      if (cc === '-') {
+        return '.';
+      } else if (cc.charAt(0) === 'z') {
+        return String.fromCharCode(Number(cc.slice(1, -1)));
+      } else {
+        return cc;
+      }
+    })
   /**
    * Returns whether a string has the expected format to be used as a secret token identifying an
    * author. The format is defined as: 't.' followed by a non-empty base64url string (RFC 4648
@@ -340,109 +383,109 @@ const padutils = {
    * conditional transformation of a token to a database key in a way that does not allow a
    * malicious user to impersonate another user).
    */
-  isValidAuthorToken: (t) => {
+  isValidAuthorToken = (t: string | object) => {
     if (typeof t !== 'string' || !t.startsWith('t.')) return false;
     const v = t.slice(2);
     return v.length > 0 && base64url.test(v);
-  },
+  }
+
 
   /**
    * Returns a string that can be used in the `token` cookie as a secret that authenticates a
    * particular author.
    */
-  generateAuthorToken: () => `t.${randomString()}`,
-};
-
-let globalExceptionHandler = null;
-padutils.setupGlobalExceptionHandler = () => {
-  if (globalExceptionHandler == null) {
-    globalExceptionHandler = (e) => {
-      let type;
-      let err;
-      let msg, url, linenumber;
-      if (e instanceof ErrorEvent) {
-        type = 'Uncaught exception';
-        err = e.error || {};
-        ({message: msg, filename: url, lineno: linenumber} = e);
-      } else if (e instanceof PromiseRejectionEvent) {
-        type = 'Unhandled Promise rejection';
-        err = e.reason || {};
-        ({message: msg = 'unknown', fileName: url = 'unknown', lineNumber: linenumber = -1} = err);
-      } else {
-        throw new Error(`unknown event: ${e.toString()}`);
-      }
-      if (err.name != null && msg !== err.name && !msg.startsWith(`${err.name}: `)) {
-        msg = `${err.name}: ${msg}`;
-      }
-      const errorId = randomString(20);
-
-      let msgAlreadyVisible = false;
-      $('.gritter-item .error-msg').each(function () {
-        if ($(this).text() === msg) {
-          msgAlreadyVisible = true;
+  generateAuthorToken = () => `t.${randomString()}`
+  setupGlobalExceptionHandler = () => {
+    if (this.globalExceptionHandler == null) {
+      this.globalExceptionHandler = (e: any) => {
+        let type;
+        let err;
+        let msg, url, linenumber;
+        if (e instanceof ErrorEvent) {
+          type = 'Uncaught exception';
+          err = e.error || {};
+          ({message: msg, filename: url, lineno: linenumber} = e);
+        } else if (e instanceof PromiseRejectionEvent) {
+          type = 'Unhandled Promise rejection';
+          err = e.reason || {};
+          ({message: msg = 'unknown', fileName: url = 'unknown', lineNumber: linenumber = -1} = err);
+        } else {
+          throw new Error(`unknown event: ${e.toString()}`);
         }
-      });
+        if (err.name != null && msg !== err.name && !msg.startsWith(`${err.name}: `)) {
+          msg = `${err.name}: ${msg}`;
+        }
+        const errorId = randomString(20);
 
-      if (!msgAlreadyVisible) {
-        const txt = document.createTextNode.bind(document); // Convenience shorthand.
-        const errorMsg = [
-          $('<p>')
+        let msgAlreadyVisible = false;
+        $('.gritter-item .error-msg').each(function () {
+          if ($(this).text() === msg) {
+            msgAlreadyVisible = true;
+          }
+        });
+
+        if (!msgAlreadyVisible) {
+          const txt = document.createTextNode.bind(document); // Convenience shorthand.
+          const errorMsg = [
+            $('<p>')
               .append($('<b>').text('Please press and hold Ctrl and press F5 to reload this page')),
-          $('<p>')
+            $('<p>')
               .text('If the problem persists, please send this error message to your webmaster:'),
-          $('<div>').css('text-align', 'left').css('font-size', '.8em').css('margin-top', '1em')
+            $('<div>').css('text-align', 'left').css('font-size', '.8em').css('margin-top', '1em')
               .append($('<b>').addClass('error-msg').text(msg)).append($('<br>'))
               .append(txt(`at ${url} at line ${linenumber}`)).append($('<br>'))
               .append(txt(`ErrorId: ${errorId}`)).append($('<br>'))
               .append(txt(type)).append($('<br>'))
               .append(txt(`URL: ${window.location.href}`)).append($('<br>'))
               .append(txt(`UserAgent: ${navigator.userAgent}`)).append($('<br>')),
-        ];
+          ];
 
-        $.gritter.add({
-          title: 'An error occurred',
-          text: errorMsg,
-          class_name: 'error',
-          position: 'bottom',
-          sticky: true,
+          // @ts-ignore
+          $.gritter.add({
+            title: 'An error occurred',
+            text: errorMsg,
+            class_name: 'error',
+            position: 'bottom',
+            sticky: true,
+          });
+        }
+
+        // send javascript errors to the server
+        $.post('../jserror', {
+          errorInfo: JSON.stringify({
+            errorId,
+            type,
+            msg,
+            url: window.location.href,
+            source: url,
+            linenumber,
+            userAgent: navigator.userAgent,
+            stack: err.stack,
+          }),
         });
-      }
-
-      // send javascript errors to the server
-      $.post('../jserror', {
-        errorInfo: JSON.stringify({
-          errorId,
-          type,
-          msg,
-          url: window.location.href,
-          source: url,
-          linenumber,
-          userAgent: navigator.userAgent,
-          stack: err.stack,
-        }),
-      });
-    };
-    window.onerror = null; // Clear any pre-existing global error handler.
-    window.addEventListener('error', globalExceptionHandler);
-    window.addEventListener('unhandledrejection', globalExceptionHandler);
+      };
+      window.onerror = null; // Clear any pre-existing global error handler.
+      window.addEventListener('error', this.globalExceptionHandler);
+      window.addEventListener('unhandledrejection', this.globalExceptionHandler);
+    }
   }
-};
-
-padutils.binarySearch = require('./ace2_common').binarySearch;
+  binarySearch = binarySearch
+}
 
 // https://stackoverflow.com/a/42660748
 const inThirdPartyIframe = () => {
   try {
-    return (!window.top.location.hostname);
+    return (!window.top!.location.hostname);
   } catch (e) {
     return true;
   }
 };
 
+export let Cookies: CookiesStatic<string>
 // This file is included from Node so that it can reuse randomString, but Node doesn't have a global
 // window object.
 if (typeof window !== 'undefined') {
-  exports.Cookies = require('js-cookie').withAttributes({
+  Cookies = jsCookie.withAttributes({
     // Use `SameSite=Lax`, unless Etherpad is embedded in an iframe from another site in which case
     // use `SameSite=None`. For iframes from another site, only `None` has a chance of working
     // because the cookies are third-party (not same-site). Many browsers/users block third-party
@@ -455,5 +498,5 @@ if (typeof window !== 'undefined') {
     secure: window.location.protocol === 'https:',
   });
 }
-exports.randomString = randomString;
-exports.padutils = padutils;
+
+export default new PadUtils()
diff --git a/src/static/js/pluginfw/client_plugins.js b/src/static/js/pluginfw/client_plugins.ts
similarity index 99%
rename from src/static/js/pluginfw/client_plugins.js
rename to src/static/js/pluginfw/client_plugins.ts
index 3a0687733..0688d12ca 100644
--- a/src/static/js/pluginfw/client_plugins.js
+++ b/src/static/js/pluginfw/client_plugins.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 const pluginUtils = require('./shared');
diff --git a/src/static/js/pluginfw/hooks.js b/src/static/js/pluginfw/hooks.ts
similarity index 99%
rename from src/static/js/pluginfw/hooks.js
rename to src/static/js/pluginfw/hooks.ts
index 731cbd190..a480ecf46 100644
--- a/src/static/js/pluginfw/hooks.js
+++ b/src/static/js/pluginfw/hooks.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 const pluginDefs = require('./plugin_defs');
diff --git a/src/static/js/pluginfw/plugin_defs.js b/src/static/js/pluginfw/plugin_defs.ts
similarity index 100%
rename from src/static/js/pluginfw/plugin_defs.js
rename to src/static/js/pluginfw/plugin_defs.ts
diff --git a/src/static/js/pluginfw/plugins.js b/src/static/js/pluginfw/plugins.ts
similarity index 99%
rename from src/static/js/pluginfw/plugins.js
rename to src/static/js/pluginfw/plugins.ts
index f48d6cc6d..97c1694e2 100644
--- a/src/static/js/pluginfw/plugins.js
+++ b/src/static/js/pluginfw/plugins.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 const fs = require('fs').promises;
diff --git a/src/static/js/pluginfw/shared.js b/src/static/js/pluginfw/shared.ts
similarity index 99%
rename from src/static/js/pluginfw/shared.js
rename to src/static/js/pluginfw/shared.ts
index b2c2337f6..a7c761786 100644
--- a/src/static/js/pluginfw/shared.js
+++ b/src/static/js/pluginfw/shared.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 const defs = require('./plugin_defs');
diff --git a/src/static/js/pluginfw/tsort.js b/src/static/js/pluginfw/tsort.ts
similarity index 99%
rename from src/static/js/pluginfw/tsort.js
rename to src/static/js/pluginfw/tsort.ts
index 6f0b4bf00..a067d29de 100644
--- a/src/static/js/pluginfw/tsort.js
+++ b/src/static/js/pluginfw/tsort.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/rjquery.js b/src/static/js/rjquery.ts
similarity index 93%
rename from src/static/js/rjquery.js
rename to src/static/js/rjquery.ts
index a80e1f8d3..167e96090 100644
--- a/src/static/js/rjquery.js
+++ b/src/static/js/rjquery.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 // Provides a require'able version of jQuery without leaking $ and jQuery;
 window.$ = require('./vendors/jquery');
diff --git a/src/static/js/security.js b/src/static/js/security.ts
similarity index 97%
rename from src/static/js/security.js
rename to src/static/js/security.ts
index d92425cb7..d5f9b7266 100644
--- a/src/static/js/security.js
+++ b/src/static/js/security.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/skin_variants.js b/src/static/js/skin_variants.ts
similarity index 99%
rename from src/static/js/skin_variants.js
rename to src/static/js/skin_variants.ts
index 9a0427ac9..c9783aaa3 100644
--- a/src/static/js/skin_variants.js
+++ b/src/static/js/skin_variants.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 // Specific hash to display the skin variants builder popup
diff --git a/src/static/js/skiplist.js b/src/static/js/skiplist.ts
similarity index 61%
rename from src/static/js/skiplist.js
rename to src/static/js/skiplist.ts
index f10a4e7a8..0e7724b23 100644
--- a/src/static/js/skiplist.js
+++ b/src/static/js/skiplist.ts
@@ -22,10 +22,24 @@
  * limitations under the License.
  */
 
-const _entryWidth = (e) => (e && e.width) || 0;
+const _entryWidth = (e: Entry) => (e && e.width) || 0;
+
+type Entry = {
+  key: string,
+  value?: string
+  width?: number
+}
 
 class Node {
-  constructor(entry, levels = 0, downSkips = 1, downSkipWidths = 0) {
+  public key: string|null
+  readonly entry: Entry|null
+  levels: number
+  upPtrs: Node[]
+  downPtrs: Node[]
+  downSkips: number[]
+  readonly downSkipWidths: number[]
+
+  constructor(entry: Entry|null, levels = 0, downSkips: number|null = 1, downSkipWidths:number|null  = 0) {
     this.key = entry != null ? entry.key : null;
     this.entry = entry;
     this.levels = levels;
@@ -37,9 +51,9 @@ class Node {
 
   propagateWidthChange() {
     const oldWidth = this.downSkipWidths[0];
-    const newWidth = _entryWidth(this.entry);
+    const newWidth = _entryWidth(this.entry!);
     const widthChange = newWidth - oldWidth;
-    let n = this;
+    let n: Node = this;
     let lvl = 0;
     while (lvl < n.levels) {
       n.downSkipWidths[lvl] += widthChange;
@@ -57,17 +71,23 @@ class Node {
 // is still valid and points to the same index in the skiplist. Other operations with other points
 // invalidate this point.
 class Point {
-  constructor(skipList, loc) {
-    this._skipList = skipList;
+  private skipList: SkipList
+  private readonly loc: number
+  private readonly idxs: number[]
+  private readonly nodes: Node[]
+  private widthSkips: number[]
+
+  constructor(skipList: SkipList, loc: number) {
+    this.skipList = skipList;
     this.loc = loc;
-    const numLevels = this._skipList._start.levels;
+    const numLevels = this.skipList.start.levels;
     let lvl = numLevels - 1;
     let i = -1;
     let ws = 0;
-    const nodes = new Array(numLevels);
-    const idxs = new Array(numLevels);
-    const widthSkips = new Array(numLevels);
-    nodes[lvl] = this._skipList._start;
+    const nodes: Node[] = new Array(numLevels);
+    const idxs: number[] = new Array(numLevels);
+    const widthSkips: number[] = new Array(numLevels);
+    nodes[lvl] = this.skipList.start;
     idxs[lvl] = -1;
     widthSkips[lvl] = 0;
     while (lvl >= 0) {
@@ -94,9 +114,9 @@ class Point {
     return `Point(${this.loc})`;
   }
 
-  insert(entry) {
+  insert(entry: Entry) {
     if (entry.key == null) throw new Error('entry.key must not be null');
-    if (this._skipList.containsKey(entry.key)) {
+    if (this.skipList.containsKey(entry.key)) {
       throw new Error(`an entry with key ${entry.key} already exists`);
     }
 
@@ -115,14 +135,14 @@ class Point {
       if (lvl === pNodes.length) {
         // assume we have just passed the end of this.nodes, and reached one level greater
         // than the skiplist currently supports
-        pNodes[lvl] = this._skipList._start;
+        pNodes[lvl] = this.skipList.start;
         pIdxs[lvl] = -1;
-        this._skipList._start.levels++;
-        this._skipList._end.levels++;
-        this._skipList._start.downPtrs[lvl] = this._skipList._end;
-        this._skipList._end.upPtrs[lvl] = this._skipList._start;
-        this._skipList._start.downSkips[lvl] = this._skipList._keyToNodeMap.size + 1;
-        this._skipList._start.downSkipWidths[lvl] = this._skipList._totalWidth;
+        this.skipList.start.levels++;
+        this.skipList.end.levels++;
+        this.skipList.start.downPtrs[lvl] = this.skipList.end;
+        this.skipList.end.upPtrs[lvl] = this.skipList.start;
+        this.skipList.start.downSkips[lvl] = this.skipList.keyToNodeMap.size + 1;
+        this.skipList.start.downSkipWidths[lvl] = this.skipList._totalWidth;
         this.widthSkips[lvl] = 0;
       }
       const me = newNode;
@@ -146,13 +166,13 @@ class Point {
       up.downSkips[lvl]++;
       up.downSkipWidths[lvl] += newWidth;
     }
-    this._skipList._keyToNodeMap.set(newNode.key, newNode);
-    this._skipList._totalWidth += newWidth;
+    this.skipList.keyToNodeMap.set(newNode.key as string, newNode);
+    this.skipList._totalWidth += newWidth;
   }
 
   delete() {
     const elem = this.nodes[0].downPtrs[0];
-    const elemWidth = _entryWidth(elem.entry);
+    const elemWidth = _entryWidth(elem.entry!);
     for (let i = 0; i < this.nodes.length; i++) {
       if (i < elem.levels) {
         const up = elem.upPtrs[i];
@@ -169,8 +189,8 @@ class Point {
         up.downSkipWidths[i] -= elemWidth;
       }
     }
-    this._skipList._keyToNodeMap.delete(elem.key);
-    this._skipList._totalWidth -= elemWidth;
+    this.skipList.keyToNodeMap.delete(elem.key as string);
+    this.skipList._totalWidth -= elemWidth;
   }
 
   getNode() {
@@ -183,20 +203,26 @@ class Point {
  * property that is a string.
  */
 class SkipList {
+  start: Node
+  end: Node
+  _totalWidth: number
+  keyToNodeMap: Map<string, Node>
+
+
   constructor() {
     // if there are N elements in the skiplist, "start" is element -1 and "end" is element N
-    this._start = new Node(null, 1);
-    this._end = new Node(null, 1, null, null);
+    this.start = new Node(null, 1);
+    this.end = new Node(null, 1, null, null);
     this._totalWidth = 0;
-    this._keyToNodeMap = new Map();
-    this._start.downPtrs[0] = this._end;
-    this._end.upPtrs[0] = this._start;
+    this.keyToNodeMap = new Map();
+    this.start.downPtrs[0] = this.end;
+    this.end.upPtrs[0] = this.start;
   }
 
-  _getNodeAtOffset(targetOffset) {
+  _getNodeAtOffset(targetOffset: number) {
     let i = 0;
-    let n = this._start;
-    let lvl = this._start.levels - 1;
+    let n = this.start;
+    let lvl = this.start.levels - 1;
     while (lvl >= 0 && n.downPtrs[lvl]) {
       while (n.downPtrs[lvl] && (i + n.downSkipWidths[lvl] <= targetOffset)) {
         i += n.downSkipWidths[lvl];
@@ -204,17 +230,17 @@ class SkipList {
       }
       lvl--;
     }
-    if (n === this._start) return (this._start.downPtrs[0] || null);
-    if (n === this._end) {
-      return targetOffset === this._totalWidth ? (this._end.upPtrs[0] || null) : null;
+    if (n === this.start) return (this.start.downPtrs[0] || null);
+    if (n === this.end) {
+      return targetOffset === this._totalWidth ? (this.end.upPtrs[0] || null) : null;
     }
     return n;
   }
 
-  _getNodeIndex(node, byWidth) {
+  _getNodeIndex(node: Node, byWidth?: boolean) {
     let dist = (byWidth ? 0 : -1);
     let n = node;
-    while (n !== this._start) {
+    while (n !== this.start) {
       const lvl = n.levels - 1;
       n = n.upPtrs[lvl];
       if (byWidth) dist += n.downSkipWidths[lvl];
@@ -223,17 +249,19 @@ class SkipList {
     return dist;
   }
 
+  totalWidth() { return this._totalWidth; }
+
   // Returns index of first entry such that entryFunc(entry) is truthy,
   // or length() if no such entry.  Assumes all falsy entries come before
   // all truthy entries.
-  search(entryFunc) {
-    let low = this._start;
-    let lvl = this._start.levels - 1;
+  search(entryFunc: Function) {
+    let low = this.start;
+    let lvl = this.start.levels - 1;
     let lowIndex = -1;
 
-    const f = (node) => {
-      if (node === this._start) return false;
-      else if (node === this._end) return true;
+    const f = (node: Node) => {
+      if (node === this.start) return false;
+      else if (node === this.end) return true;
       else return entryFunc(node.entry);
     };
 
@@ -249,20 +277,20 @@ class SkipList {
     return lowIndex + 1;
   }
 
-  length() { return this._keyToNodeMap.size; }
+  length() { return this.keyToNodeMap.size; }
 
-  atIndex(i) {
+  atIndex(i: number) {
     if (i < 0) console.warn(`atIndex(${i})`);
-    if (i >= this._keyToNodeMap.size) console.warn(`atIndex(${i}>=${this._keyToNodeMap.size})`);
+    if (i >= this.keyToNodeMap.size) console.warn(`atIndex(${i}>=${this.keyToNodeMap.size})`);
     return (new Point(this, i)).getNode().entry;
   }
 
   // differs from Array.splice() in that new elements are in an array, not varargs
-  splice(start, deleteCount, newEntryArray) {
+  splice(start: number, deleteCount: number, newEntryArray: Entry[]) {
     if (start < 0) console.warn(`splice(${start}, ...)`);
-    if (start + deleteCount > this._keyToNodeMap.size) {
-      console.warn(`splice(${start}, ${deleteCount}, ...), N=${this._keyToNodeMap.size}`);
-      console.warn('%s %s %s', typeof start, typeof deleteCount, typeof this._keyToNodeMap.size);
+    if (start + deleteCount > this.keyToNodeMap.size) {
+      console.warn(`splice(${start}, ${deleteCount}, ...), N=${this.keyToNodeMap.size}`);
+      console.warn('%s %s %s', typeof start, typeof deleteCount, typeof this.keyToNodeMap.size);
       console.trace();
     }
 
@@ -275,56 +303,55 @@ class SkipList {
     }
   }
 
-  next(entry) { return this._keyToNodeMap.get(entry.key).downPtrs[0].entry || null; }
-  prev(entry) { return this._keyToNodeMap.get(entry.key).upPtrs[0].entry || null; }
-  push(entry) { this.splice(this._keyToNodeMap.size, 0, [entry]); }
+  next(entry: Entry) { return this.keyToNodeMap.get(entry.key)!.downPtrs[0].entry || null; }
+  prev(entry: Entry) { return this.keyToNodeMap.get(entry.key)!.upPtrs[0].entry || null; }
+  push(entry: Entry) { this.splice(this.keyToNodeMap.size, 0, [entry]); }
 
-  slice(start, end) {
+  slice(start: number, end: number) {
     // act like Array.slice()
     if (start === undefined) start = 0;
-    else if (start < 0) start += this._keyToNodeMap.size;
-    if (end === undefined) end = this._keyToNodeMap.size;
-    else if (end < 0) end += this._keyToNodeMap.size;
+    else if (start < 0) start += this.keyToNodeMap.size;
+    if (end === undefined) end = this.keyToNodeMap.size;
+    else if (end < 0) end += this.keyToNodeMap.size;
 
     if (start < 0) start = 0;
-    if (start > this._keyToNodeMap.size) start = this._keyToNodeMap.size;
+    if (start > this.keyToNodeMap.size) start = this.keyToNodeMap.size;
     if (end < 0) end = 0;
-    if (end > this._keyToNodeMap.size) end = this._keyToNodeMap.size;
+    if (end > this.keyToNodeMap.size) end = this.keyToNodeMap.size;
 
     if (end <= start) return [];
     let n = this.atIndex(start);
     const array = [n];
     for (let i = 1; i < (end - start); i++) {
-      n = this.next(n);
+      n = this.next(n!);
       array.push(n);
     }
     return array;
   }
 
-  atKey(key) { return this._keyToNodeMap.get(key).entry; }
-  indexOfKey(key) { return this._getNodeIndex(this._keyToNodeMap.get(key)); }
-  indexOfEntry(entry) { return this.indexOfKey(entry.key); }
-  containsKey(key) { return this._keyToNodeMap.has(key); }
+  atKey(key: string) { return this.keyToNodeMap.get(key)!.entry; }
+  indexOfKey(key: string) { return this._getNodeIndex(this.keyToNodeMap.get(key)!); }
+  indexOfEntry(entry: Entry) { return this.indexOfKey(entry.key); }
+  containsKey(key: string) { return this.keyToNodeMap.has(key); }
   // gets the last entry starting at or before the offset
-  atOffset(offset) { return this._getNodeAtOffset(offset).entry; }
-  keyAtOffset(offset) { return this.atOffset(offset).key; }
-  offsetOfKey(key) { return this._getNodeIndex(this._keyToNodeMap.get(key), true); }
-  offsetOfEntry(entry) { return this.offsetOfKey(entry.key); }
-  setEntryWidth(entry, width) {
+  atOffset(offset: number) { return this._getNodeAtOffset(offset)!.entry; }
+  keyAtOffset(offset: number) { return this.atOffset(offset)!.key; }
+  offsetOfKey(key: string) { return this._getNodeIndex(this.keyToNodeMap.get(key)!, true); }
+  offsetOfEntry(entry: Entry) { return this.offsetOfKey(entry.key); }
+  setEntryWidth(entry: Entry, width: number) {
     entry.width = width;
-    this._totalWidth += this._keyToNodeMap.get(entry.key).propagateWidthChange();
+    this._totalWidth += this.keyToNodeMap.get(entry.key)!.propagateWidthChange();
   }
-  totalWidth() { return this._totalWidth; }
-  offsetOfIndex(i) {
+  offsetOfIndex(i: number) {
     if (i < 0) return 0;
-    if (i >= this._keyToNodeMap.size) return this._totalWidth;
-    return this.offsetOfEntry(this.atIndex(i));
+    if (i >= this.keyToNodeMap.size) return this._totalWidth;
+    return this.offsetOfEntry(this.atIndex(i)!);
   }
-  indexOfOffset(offset) {
+  indexOfOffset(offset: number) {
     if (offset <= 0) return 0;
-    if (offset >= this._totalWidth) return this._keyToNodeMap.size;
-    return this.indexOfEntry(this.atOffset(offset));
+    if (offset >= this._totalWidth) return this.keyToNodeMap.size;
+    return this.indexOfEntry(this.atOffset(offset)!);
   }
 }
 
-module.exports = SkipList;
+export default SkipList
diff --git a/src/static/js/socketio.js b/src/static/js/socketio.ts
similarity index 99%
rename from src/static/js/socketio.js
rename to src/static/js/socketio.ts
index cdc1c9a23..aedd68c20 100644
--- a/src/static/js/socketio.js
+++ b/src/static/js/socketio.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 import io from 'socket.io-client';
 
 /**
diff --git a/src/static/js/timeslider.js b/src/static/js/timeslider.ts
similarity index 97%
rename from src/static/js/timeslider.js
rename to src/static/js/timeslider.ts
index 8d8604b91..befc4f8b7 100644
--- a/src/static/js/timeslider.js
+++ b/src/static/js/timeslider.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
@@ -26,10 +27,9 @@
 // assigns to the global `$` and augments it with plugins.
 require('./vendors/jquery');
 
-const Cookies = require('./pad_utils').Cookies;
-const randomString = require('./pad_utils').randomString;
+import {randomString, Cookies} from "./pad_utils";
 const hooks = require('./pluginfw/hooks');
-const padutils = require('./pad_utils').padutils;
+import padutils from './pad_utils'
 const socketio = require('./socketio');
 import html10n from '../js/vendors/html10n'
 let token, padId, exportLinks, socket, changesetLoader, BroadcastSlider;
diff --git a/src/static/js/types/AText.ts b/src/static/js/types/AText.ts
new file mode 100644
index 000000000..d58626de2
--- /dev/null
+++ b/src/static/js/types/AText.ts
@@ -0,0 +1,4 @@
+export type AText = {
+  text: string,
+  attribs: string,
+}
diff --git a/src/static/js/types/Attribute.ts b/src/static/js/types/Attribute.ts
new file mode 100644
index 000000000..f1c06b3cb
--- /dev/null
+++ b/src/static/js/types/Attribute.ts
@@ -0,0 +1 @@
+export type Attribute = [string, string]
diff --git a/src/static/js/types/PadRevision.ts b/src/static/js/types/PadRevision.ts
new file mode 100644
index 000000000..c54dc4379
--- /dev/null
+++ b/src/static/js/types/PadRevision.ts
@@ -0,0 +1,7 @@
+export type PadRevision = {
+  revNum: number;
+  savedById: string;
+  label: string;
+  timestamp: number;
+  id: string;
+}
diff --git a/src/static/js/types/SocketIOMessage.ts b/src/static/js/types/SocketIOMessage.ts
new file mode 100644
index 000000000..9c9ffea7f
--- /dev/null
+++ b/src/static/js/types/SocketIOMessage.ts
@@ -0,0 +1,317 @@
+import {MapArrayType} from "../../../node/types/MapType";
+import {AText} from "./AText";
+import AttributePool from "../AttributePool";
+import attributePool from "../AttributePool";
+import ChatMessage from "../ChatMessage";
+import {PadRevision} from "./PadRevision";
+
+export type Part = {
+  name: string,
+  client_hooks: MapArrayType<string>,
+  hooks: MapArrayType<string>
+  pre?: string[]
+  post?: string[]
+  plugin?: string
+}
+
+
+export type MappedPlugin = Part& {
+  plugin: string
+  full_name: string
+}
+
+export type SocketIOMessage = {
+  type: string
+  accessStatus: string
+}
+
+export type HistoricalAuthorData = MapArrayType<{
+  name: string;
+  colorId: number;
+  userId?: string
+}>
+
+export type ServerVar = {
+  rev: number
+  clientIp: string
+  padId: string
+  historicalAuthorData?: HistoricalAuthorData,
+  initialAttributedText: {
+    attribs: string
+    text: string
+  },
+  apool: AttributePoolWire
+  time: number
+}
+
+export type AttributePoolWire = {numToAttrib: {[p: number]: [string, string]}, nextNum: number}
+
+
+export type UserInfo = {
+  userId: string
+  colorId: string,
+  name: string|null
+}
+
+export type ClientVarPayload = {
+  readOnlyId: string
+  automaticReconnectionTimeout: number
+  sessionRefreshInterval: number,
+  atext?: AText,
+  apool?: AttributePool,
+  userName?: string,
+  userColor: number,
+  hideChat?: boolean,
+  padOptions: PadOption,
+  padId: string,
+  clientIp: string,
+  colorPalette: string[],
+  accountPrivs: {
+    maxRevisions: number,
+  },
+  collab_client_vars: ServerVar,
+  chatHead: number,
+  readonly: boolean,
+  serverTimestamp: number,
+  initialOptions: MapArrayType<string>,
+  userId: string,
+  mode: string,
+  randomVersionString: string,
+  skinName: string
+  skinVariants: string,
+  exportAvailable: string
+  savedRevisions: PadRevision[],
+  initialRevisionList: number[],
+  padShortcutEnabled: MapArrayType<boolean>,
+  initialTitle: string,
+  opts: {}
+  numConnectedUsers: number
+  abiwordAvailable: string
+  sofficeAvailable: string
+  plugins: {
+    plugins:  MapArrayType<any>
+    parts:  MappedPlugin[]
+  }
+  indentationOnNewLine: boolean
+  scrollWhenFocusLineIsOutOfViewport : {
+    percentage: {
+      editionAboveViewport: number,
+      editionBelowViewport: number
+    }
+    duration: number
+    scrollWhenCaretIsInTheLastLineOfViewport: boolean
+    percentageToScrollWhenUserPressesArrowUp: number
+  }
+  initialChangesets: []
+}
+
+export type ClientVarData = {
+  type: "CLIENT_VARS"
+  data: ClientVarPayload
+}
+
+export type ClientNewChanges = {
+  type : 'NEW_CHANGES'
+  apool: AttributePool,
+  author: string,
+  changeset: string,
+  newRev: number,
+  payload?: ClientNewChanges
+}
+
+export type ClientAcceptCommitMessage = {
+  type: 'ACCEPT_COMMIT'
+  newRev: number
+}
+
+export type ClientConnectMessage = {
+  type: 'CLIENT_RECONNECT',
+  noChanges: boolean,
+  headRev: number,
+  newRev: number,
+  changeset: string,
+  author: string
+  apool: AttributePool
+}
+
+
+export type UserNewInfoMessage = {
+  type: 'USER_NEWINFO',
+  data: {
+    userInfo: UserInfo
+  }
+}
+
+export type UserLeaveMessage = {
+  type: 'USER_LEAVE'
+  userInfo: UserInfo
+}
+
+
+
+export type ClientMessageMessage = {
+  type: 'CLIENT_MESSAGE',
+  payload: ClientSendMessages
+}
+
+export type ChatMessageMessage = {
+  type: 'CHAT_MESSAGE'
+  data: {
+    message: ChatMessage
+  }
+}
+
+export type ChatMessageMessages = {
+  type: 'CHAT_MESSAGES'
+  messages: string
+}
+
+export type ClientUserChangesMessage = {
+  type: 'USER_CHANGES',
+  baseRev: number,
+  changeset: string,
+  apool: attributePool
+}
+
+
+
+export type ClientSendMessages =  ClientUserChangesMessage |ClientReadyMessage| ClientSendUserInfoUpdate|ChatMessageMessage| ClientMessageMessage | GetChatMessageMessage |ClientSuggestUserName | NewRevisionListMessage | RevisionLabel | PadOptionsMessage| ClientSaveRevisionMessage
+
+export type ClientReadyMessage = {
+  type: 'CLIENT_READY',
+  component: string,
+  padId: string,
+  sessionID: string,
+  token: string,
+  userInfo: UserInfo,
+  reconnect?: boolean
+  client_rev?: number
+}
+
+export type ClientSaveRevisionMessage = {
+  type: 'SAVE_REVISION'
+}
+
+export type GetChatMessageMessage = {
+  type: 'GET_CHAT_MESSAGES',
+  start: number,
+  end: number
+}
+
+export type ClientSendUserInfoUpdate = {
+  type: 'USERINFO_UPDATE',
+  userInfo: UserInfo
+}
+
+export type ClientSuggestUserName = {
+  type: 'suggestUserName',
+  data: {
+    payload: {
+      unnamedId: string,
+      newName: string
+    }
+  }
+}
+
+export type NewRevisionListMessage = {
+  type: 'newRevisionList',
+  revisionList: number[]
+}
+
+export type RevisionLabel = {
+  type:  'revisionLabel'
+  revisionList: number[]
+}
+
+export type PadOptionsMessage = {
+  type: 'padoptions'
+  options: PadOption
+  changedBy: string
+}
+
+export type PadOption = {
+  "noColors"?:         boolean,
+  "showControls"?:     boolean,
+  "showChat"?:         boolean,
+  "showLineNumbers"?:  boolean,
+  "useMonospaceFont"?: boolean,
+  "userName"?:         null|string,
+  "userColor"?:        null|string,
+  "rtl"?:              boolean,
+  "alwaysShowChat"?:   boolean,
+  "chatAndUsers"?:     boolean,
+  "lang"?:             null|string,
+  view? : MapArrayType<boolean>
+}
+
+
+type SharedMessageType = {
+  payload:{
+    timestamp: number
+  }
+}
+
+export type x = {
+  disconnect: boolean
+}
+
+export type ClientDisconnectedMessage = {
+  type: "disconnected"
+  disconnected: boolean
+}
+
+export type UserChanges = {
+  data: ClientUserChangesMessage
+}
+
+export type UserSuggestUserName = {
+  data: {
+    payload: ClientSuggestUserName
+  }
+}
+
+export type ChangesetRequestMessage = {
+  type: 'CHANGESET_REQ'
+  data: {
+    granularity: number
+    start: number
+    requestID: string
+  }
+}
+
+
+
+export type CollabroomMessage = {
+  type: 'COLLABROOM'
+  data: ClientSendUserInfoUpdate | ClientUserChangesMessage | ChatMessageMessage | GetChatMessageMessage | ClientSaveRevisionMessage | ClientMessageMessage
+}
+
+export type ClientVarMessage =  | ClientVarData | ClientDisconnectedMessage | ClientReadyMessage| ChangesetRequestMessage | CollabroomMessage | CustomMessage
+
+
+export type CustomMessage = {
+  type:  'CUSTOM'
+  data: any
+}
+
+export type ClientCustomMessage = {
+  type: 'CUSTOM',
+  action: string,
+  payload: any
+
+}
+
+export type SocketClientReadyMessage = {
+  type: string
+  component: string
+  padId: string
+  sessionID: string
+  token: string
+  userInfo: {
+    colorId: string|null
+    name: string|null
+  },
+  reconnect?: boolean
+  client_rev?: number
+}
+
diff --git a/src/static/js/underscore.js b/src/static/js/underscore.ts
similarity index 78%
rename from src/static/js/underscore.js
rename to src/static/js/underscore.ts
index d30543cab..79a3e8e7f 100644
--- a/src/static/js/underscore.js
+++ b/src/static/js/underscore.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 module.exports = require('underscore');
diff --git a/src/static/js/undomodule.js b/src/static/js/undomodule.ts
similarity index 99%
rename from src/static/js/undomodule.js
rename to src/static/js/undomodule.ts
index d0b83419d..32f651248 100644
--- a/src/static/js/undomodule.js
+++ b/src/static/js/undomodule.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 'use strict';
 
 /**
diff --git a/src/static/js/vendors/browser.js b/src/static/js/vendors/browser.ts
similarity index 99%
rename from src/static/js/vendors/browser.js
rename to src/static/js/vendors/browser.ts
index 2516a325b..a785d8a8e 100644
--- a/src/static/js/vendors/browser.js
+++ b/src/static/js/vendors/browser.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 // WARNING: This file may have been modified from original.
 // TODO: Check requirement of this file, this afaik was to cover weird edge cases
 // that have probably been fixed in browsers.
diff --git a/src/static/js/vendors/farbtastic.js b/src/static/js/vendors/farbtastic.ts
similarity index 99%
rename from src/static/js/vendors/farbtastic.js
rename to src/static/js/vendors/farbtastic.ts
index 5d0c4718c..d9a4d6311 100644
--- a/src/static/js/vendors/farbtastic.js
+++ b/src/static/js/vendors/farbtastic.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 // WARNING: This file has been modified from original.
 // TODO: Replace with https://github.com/Simonwep/pickr
 
diff --git a/src/static/js/vendors/gritter.js b/src/static/js/vendors/gritter.ts
similarity index 99%
rename from src/static/js/vendors/gritter.js
rename to src/static/js/vendors/gritter.ts
index 1b8b9a759..993514c74 100644
--- a/src/static/js/vendors/gritter.js
+++ b/src/static/js/vendors/gritter.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 // WARNING: This file has been modified from the Original
 
 /*
diff --git a/src/static/js/vendors/jquery.js b/src/static/js/vendors/jquery.ts
similarity index 99%
rename from src/static/js/vendors/jquery.js
rename to src/static/js/vendors/jquery.ts
index bca73371f..1b9923a62 100644
--- a/src/static/js/vendors/jquery.js
+++ b/src/static/js/vendors/jquery.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 /*!
  * jQuery JavaScript Library v3.7.1
  * https://jquery.com/
diff --git a/src/static/js/vendors/nice-select.js b/src/static/js/vendors/nice-select.ts
similarity index 99%
rename from src/static/js/vendors/nice-select.js
rename to src/static/js/vendors/nice-select.ts
index 447ff6413..ec76b3cef 100644
--- a/src/static/js/vendors/nice-select.js
+++ b/src/static/js/vendors/nice-select.ts
@@ -1,3 +1,4 @@
+// @ts-nocheck
 // WARNING: This file has been modified from the Original
 // TODO: Nice Select seems relatively abandoned, we should consider other options.
 
diff --git a/src/templates/timeslider.html b/src/templates/timeslider.html
index e2178e54e..4ef6928ff 100644
--- a/src/templates/timeslider.html
+++ b/src/templates/timeslider.html
@@ -29,7 +29,6 @@
     for the JavaScript code in this page.|
     */
   </script>
-  <script src="../../static/js/basic_error_handler.js?v=<%=settings.randomVersionString%>"></script>
   <meta charset="utf-8">
   <link rel="manifest" href="/manifest.json" />
   <meta name="robots" content="noindex, nofollow">
diff --git a/src/tests/backend-new/specs/AttributeMap.ts b/src/tests/backend-new/specs/AttributeMap.ts
index 3e43abf7c..ce5e61f74 100644
--- a/src/tests/backend-new/specs/AttributeMap.ts
+++ b/src/tests/backend-new/specs/AttributeMap.ts
@@ -1,17 +1,18 @@
 'use strict';
 
-const AttributeMap = require('../../../static/js/AttributeMap.js');
-const AttributePool = require('../../../static/js/AttributePool');
-const attributes = require('../../../static/js/attributes');
+import AttributeMap from '../../../static/js/AttributeMap';
+import AttributePool from '../../../static/js/AttributePool';
+import attributes from '../../../static/js/attributes';
 import {expect, describe, it, beforeEach} from 'vitest'
+import {Attribute} from "../../../static/js/types/Attribute";
 
 describe('AttributeMap', function () {
-  const attribs = [
+  const attribs: Attribute[] = [
     ['foo', 'bar'],
     ['baz', 'bif'],
     ['emptyValue', ''],
   ];
-  let pool: { eachAttrib: (arg0: () => number) => void; putAttrib: (arg0: string[]) => any; getAttrib: (arg0: number) => any; };
+  let pool: AttributePool;
 
   const getPoolSize = () => {
     let n = 0;
@@ -70,12 +71,14 @@ describe('AttributeMap', function () {
         describe(desc as string, function () {
           it('key is coerced to string', async function () {
             const m = new AttributeMap(pool);
+            // @ts-ignore
             m.set(input, 'value');
             expect(m.get(want)).to.equal('value');
           });
 
           it('value is coerced to string', async function () {
             const m = new AttributeMap(pool);
+            // @ts-ignore
             m.set('key', input);
             expect(m.get('key')).to.equal(want);
           });
@@ -122,6 +125,7 @@ describe('AttributeMap', function () {
         // @ts-ignore
         args[0] = attributes.attribsToString(attributes.sort([...args[0]]), pool);
       }
+      // @ts-ignore
       return AttributeMap.prototype[funcName].call(m, ...args);
     };
 
diff --git a/src/tests/backend-new/specs/attributes.ts b/src/tests/backend-new/specs/attributes.ts
index 5f33f52b3..64a4464bd 100644
--- a/src/tests/backend-new/specs/attributes.ts
+++ b/src/tests/backend-new/specs/attributes.ts
@@ -2,14 +2,15 @@
 
 import {APool} from "../../../node/types/PadType";
 
-const AttributePool = require('../../../static/js/AttributePool');
-const attributes = require('../../../static/js/attributes');
+import AttributePool from '../../../static/js/AttributePool';
+import attributes from '../../../static/js/attributes';
 
 import {expect, describe, it, beforeEach} from 'vitest';
+import {Attribute} from "../../../static/js/types/Attribute";
 
 describe('attributes', function () {
-  const attribs = [['foo', 'bar'], ['baz', 'bif']];
-  let pool: APool;
+  const attribs: Attribute[] = [['foo', 'bar'], ['baz', 'bif']];
+  let pool: AttributePool;
 
   beforeEach(async function () {
     pool = new AttributePool();
@@ -45,6 +46,7 @@ describe('attributes', function () {
       ];
       for (const [input, want] of testCases) {
         it(`${JSON.stringify(input)} -> ${JSON.stringify(want)}`, async function () {
+          // @ts-ignore
           const got = [...attributes.decodeAttribString(input)];
           expect(JSON.stringify(got)).to.equal(JSON.stringify(want));
         });
@@ -61,6 +63,7 @@ describe('attributes', function () {
       ];
       for (const [desc, input] of testCases) {
         it(desc as string, async function () {
+          // @ts-ignore
           expect(attributes.encodeAttribString(input)).to.equal('*0*1');
         });
       }
@@ -78,6 +81,7 @@ describe('attributes', function () {
       ];
       for (const [input, wantErr] of testCases) {
         it(JSON.stringify(input), async function () {
+          // @ts-ignore
           expect(() => attributes.encodeAttribString(input)).toThrowError(wantErr as RegExp);
         });
       }
@@ -97,6 +101,7 @@ describe('attributes', function () {
       ];
       for (const [input, want] of testCases) {
         it(`${JSON.stringify(input)} -> ${JSON.stringify(want)}`, async function () {
+          // @ts-ignore
           expect(attributes.encodeAttribString(input)).to.equal(want);
         });
       }
@@ -117,6 +122,7 @@ describe('attributes', function () {
 
       for (const [desc, input] of testCases) {
         it(desc as string, async function () {
+          // @ts-ignore
           const gotAttribs = [...attributes.attribsFromNums(input, pool)];
           expect(JSON.stringify(gotAttribs)).to.equal(JSON.stringify(attribs));
         });
@@ -136,6 +142,7 @@ describe('attributes', function () {
       ];
       for (const [input, wantErr] of testCases) {
         it(JSON.stringify(input), async function () {
+          // @ts-ignore
           expect(() => [...attributes.attribsFromNums(input, pool)]).toThrowError(wantErr as RegExp);
         });
       }
@@ -151,6 +158,7 @@ describe('attributes', function () {
       ];
       for (const [input, want] of testCases) {
         it(`${JSON.stringify(input)} -> ${JSON.stringify(want)}`, async function () {
+          // @ts-ignore
           const gotAttribs = [...attributes.attribsFromNums(input, pool)];
           expect(JSON.stringify(gotAttribs)).to.equal(JSON.stringify(want));
         });
@@ -172,6 +180,7 @@ describe('attributes', function () {
 
       for (const [desc, input] of testCases) {
         it(desc as string, async function () {
+          // @ts-ignore
           const gotNums = [...attributes.attribsToNums(input, pool)];
           expect(JSON.stringify(gotNums)).to.equal(JSON.stringify([0, 1]));
         });
@@ -182,6 +191,7 @@ describe('attributes', function () {
       const testCases = [null, [null]];
       for (const input of testCases) {
         it(JSON.stringify(input), async function () {
+          // @ts-ignore
           expect(() => [...attributes.attribsToNums(input, pool)]).toThrowError();
         });
       }
@@ -197,6 +207,7 @@ describe('attributes', function () {
       ];
       for (const [input, want] of testCases) {
         it(`${JSON.stringify(input)} -> ${JSON.stringify(want)}`, async function () {
+          // @ts-ignore
           const got = [...attributes.attribsToNums(input, pool)];
           expect(JSON.stringify(got)).to.equal(JSON.stringify(want));
         });
@@ -211,6 +222,7 @@ describe('attributes', function () {
       ];
       for (const [input, want] of testCases) {
         it(`${JSON.stringify(input)} -> ${JSON.stringify(want)}`, async function () {
+          // @ts-ignore
           const got = [...attributes.attribsToNums(input, pool)];
           expect(JSON.stringify(got)).to.equal(JSON.stringify(want));
           expect(JSON.stringify(pool.getAttrib(attribs.length)))
@@ -234,6 +246,7 @@ describe('attributes', function () {
             ['value is coerced to string', [['key', inputVal]], [['key', wantVal]]],
           ]) {
             it(desc as string, async function () {
+              // @ts-ignore
               const gotNums = [...attributes.attribsToNums(inputAttribs, pool)];
               // Each attrib in inputAttribs is expected to be new to the pool.
               const wantNums = [...Array(attribs.length + 1).keys()].slice(attribs.length);
@@ -265,6 +278,7 @@ describe('attributes', function () {
       ];
       for (const [input, wantErr] of testCases) {
         it(JSON.stringify(input), async function () {
+          // @ts-ignore
           expect(() => [...attributes.attribsFromString(input, pool)]).toThrowError(wantErr);
         });
       }
@@ -280,6 +294,7 @@ describe('attributes', function () {
       ];
       for (const [input, want] of testCases) {
         it(`${JSON.stringify(input)} -> ${JSON.stringify(want)}`, async function () {
+          // @ts-ignore
           const gotAttribs = [...attributes.attribsFromString(input, pool)];
           expect(JSON.stringify(gotAttribs)).to.equal(JSON.stringify(want));
         });
@@ -297,6 +312,7 @@ describe('attributes', function () {
 
       for (const [desc, input] of testCases) {
         it(desc as string, async function () {
+          // @ts-ignore
           const got = attributes.attribsToString(input, pool);
           expect(got).to.equal('*0*1');
         });
@@ -307,6 +323,7 @@ describe('attributes', function () {
       const testCases = [null, [null]];
       for (const input of testCases) {
         it(JSON.stringify(input), async function () {
+          // @ts-ignore
           expect(() => attributes.attribsToString(input, pool)).toThrowError();
         });
       }
@@ -322,6 +339,7 @@ describe('attributes', function () {
       ];
       for (const [input, want] of testCases) {
         it(`${JSON.stringify(input)} -> ${JSON.stringify(want)}`, async function () {
+          // @ts-ignore
           const got = attributes.attribsToString(input, pool);
           expect(got).to.equal(want);
         });
@@ -336,6 +354,7 @@ describe('attributes', function () {
       ];
       for (const [input, want] of testCases) {
         it(`${JSON.stringify(input)} -> ${JSON.stringify(want)}`, async function () {
+          // @ts-ignore
           const got = attributes.attribsToString(input, pool);
           expect(got).to.equal(want);
           expect(JSON.stringify(pool.getAttrib(attribs.length)))
diff --git a/src/tests/backend-new/specs/contentcollector.ts b/src/tests/backend-new/specs/contentcollector.ts
deleted file mode 100644
index 81f0bc2ea..000000000
--- a/src/tests/backend-new/specs/contentcollector.ts
+++ /dev/null
@@ -1,398 +0,0 @@
-'use strict';
-
-/*
- * While importexport tests target the `setHTML` API endpoint, which is nearly identical to what
- * happens when a user manually imports a document via the UI, the contentcollector tests here don't
- * use rehype to process the document. Rehype removes spaces and newĺines were applicable, so the
- * expected results here can differ from importexport.js.
- *
- * If you add tests here, please also add them to importexport.js
- */
-
-import {APool} from "../../../node/types/PadType";
-
-const AttributePool = require('../../../static/js/AttributePool');
-const Changeset = require('../../../static/js/Changeset');
-const assert = require('assert').strict;
-const attributes = require('../../../static/js/attributes');
-const contentcollector = require('../../../static/js/contentcollector');
-const jsdom = require('jsdom');
-
-import {describe, it, beforeAll, test} from 'vitest';
-
-// All test case `wantAlines` values must only refer to attributes in this list so that the
-// attribute numbers do not change due to changes in pool insertion order.
-const knownAttribs = [
-  ['insertorder', 'first'],
-  ['italic', 'true'],
-  ['list', 'bullet1'],
-  ['list', 'bullet2'],
-  ['list', 'number1'],
-  ['list', 'number2'],
-  ['lmkr', '1'],
-  ['start', '1'],
-  ['start', '2'],
-];
-
-const testCases = [
-  {
-    description: 'Simple',
-    html: '<html><body><p>foo</p></body></html>',
-    wantAlines: ['+3'],
-    wantText: ['foo'],
-  },
-  {
-    description: 'Line starts with asterisk',
-    html: '<html><body><p>*foo</p></body></html>',
-    wantAlines: ['+4'],
-    wantText: ['*foo'],
-  },
-  {
-    description: 'Complex nested Li',
-    html: '<!doctype html><html><body><ol><li>one</li><li><ol><li>1.1</li></ol></li><li>two</li></ol></body></html>',
-    wantAlines: [
-      '*0*4*6*7+1+3',
-      '*0*5*6*8+1+3',
-      '*0*4*6*8+1+3',
-    ],
-    wantText: [
-      '*one', '*1.1', '*two',
-    ],
-  },
-  {
-    description: 'Complex list of different types',
-    html: '<!doctype html><html><body><ul class="bullet"><li>one</li><li>two</li><li>0</li><li>1</li><li>2<ul class="bullet"><li>3</li><li>4</li></ul></li></ul><ol class="number"><li>item<ol class="number"><li>item1</li><li>item2</li></ol></li></ol></body></html>',
-    wantAlines: [
-      '*0*2*6+1+3',
-      '*0*2*6+1+3',
-      '*0*2*6+1+1',
-      '*0*2*6+1+1',
-      '*0*2*6+1+1',
-      '*0*3*6+1+1',
-      '*0*3*6+1+1',
-      '*0*4*6*7+1+4',
-      '*0*5*6*8+1+5',
-      '*0*5*6*8+1+5',
-    ],
-    wantText: [
-      '*one',
-      '*two',
-      '*0',
-      '*1',
-      '*2',
-      '*3',
-      '*4',
-      '*item',
-      '*item1',
-      '*item2',
-    ],
-  },
-  {
-    description: 'Tests if uls properly get attributes',
-    html: '<html><body><ul><li>a</li><li>b</li></ul><div>div</div><p>foo</p></body></html>',
-    wantAlines: [
-      '*0*2*6+1+1',
-      '*0*2*6+1+1',
-      '+3',
-      '+3',
-    ],
-    wantText: ['*a', '*b', 'div', 'foo'],
-  },
-  {
-    description: 'Tests if indented uls properly get attributes',
-    html: '<html><body><ul><li>a</li><ul><li>b</li></ul><li>a</li></ul><p>foo</p></body></html>',
-    wantAlines: [
-      '*0*2*6+1+1',
-      '*0*3*6+1+1',
-      '*0*2*6+1+1',
-      '+3',
-    ],
-    wantText: ['*a', '*b', '*a', 'foo'],
-  },
-  {
-    description: 'Tests if ols properly get line numbers when in a normal OL',
-    html: '<html><body><ol><li>a</li><li>b</li><li>c</li></ol><p>test</p></body></html>',
-    wantAlines: [
-      '*0*4*6*7+1+1',
-      '*0*4*6*7+1+1',
-      '*0*4*6*7+1+1',
-      '+4',
-    ],
-    wantText: ['*a', '*b', '*c', 'test'],
-    noteToSelf: 'Ensure empty P does not induce line attribute marker, wont this break the editor?',
-  },
-  {
-    description: 'A single completely empty line break within an ol should reset count if OL is closed off..',
-    html: '<html><body><ol><li>should be 1</li></ol><p>hello</p><ol><li>should be 1</li><li>should be 2</li></ol><p></p></body></html>',
-    wantAlines: [
-      '*0*4*6*7+1+b',
-      '+5',
-      '*0*4*6*8+1+b',
-      '*0*4*6*8+1+b',
-      '',
-    ],
-    wantText: ['*should be 1', 'hello', '*should be 1', '*should be 2', ''],
-    noteToSelf: "Shouldn't include attribute marker in the <p> line",
-  },
-  {
-    description: 'A single <p></p> should create a new line',
-    html: '<html><body><p></p><p></p></body></html>',
-    wantAlines: ['', ''],
-    wantText: ['', ''],
-    noteToSelf: '<p></p>should create a line break but not break numbering',
-  },
-  {
-    description: 'Tests if ols properly get line numbers when in a normal OL #2',
-    html: '<html><body>a<ol><li>b<ol><li>c</li></ol></ol>notlist<p>foo</p></body></html>',
-    wantAlines: [
-      '+1',
-      '*0*4*6*7+1+1',
-      '*0*5*6*8+1+1',
-      '+7',
-      '+3',
-    ],
-    wantText: ['a', '*b', '*c', 'notlist', 'foo'],
-    noteToSelf: 'Ensure empty P does not induce line attribute marker, wont this break the editor?',
-  },
-  {
-    description: 'First item being an UL then subsequent being OL will fail',
-    html: '<html><body><ul><li>a<ol><li>b</li><li>c</li></ol></li></ul></body></html>',
-    wantAlines: ['+1', '*0*1*2*3+1+1', '*0*4*2*5+1+1'],
-    wantText: ['a', '*b', '*c'],
-    noteToSelf: 'Ensure empty P does not induce line attribute marker, wont this break the editor?',
-    disabled: true,
-  },
-  {
-    description: 'A single completely empty line break within an ol should NOT reset count',
-    html: '<html><body><ol><li>should be 1</li><p></p><li>should be 2</li><li>should be 3</li></ol><p></p></body></html>',
-    wantAlines: [],
-    wantText: ['*should be 1', '*should be 2', '*should be 3'],
-    noteToSelf: "<p></p>should create a line break but not break numbering -- This is what I can't get working!",
-    disabled: true,
-  },
-  {
-    description: 'Content outside body should be ignored',
-    html: '<html><head><title>title</title><style></style></head><body>empty<br></body></html>',
-    wantAlines: ['+5'],
-    wantText: ['empty'],
-  },
-  {
-    description: 'Multiple spaces should be preserved',
-    html: '<html><body>Text with  more   than    one space.<br></body></html>',
-    wantAlines: ['+10'],
-    wantText: ['Text with  more   than    one space.'],
-  },
-  {
-    description: 'non-breaking and normal space should be preserved',
-    html: '<html><body>Text&nbsp;with&nbsp; more&nbsp;&nbsp;&nbsp;than   &nbsp;one space.<br></body></html>',
-    wantAlines: ['+10'],
-    wantText: ['Text with  more   than    one space.'],
-  },
-  {
-    description: 'Multiple nbsp should be preserved',
-    html: '<html><body>&nbsp;&nbsp;<br></body></html>',
-    wantAlines: ['+2'],
-    wantText: ['  '],
-  },
-  {
-    description: 'Multiple nbsp between words ',
-    html: '<html><body>&nbsp;&nbsp;word1&nbsp;&nbsp;word2&nbsp;&nbsp;&nbsp;word3<br></body></html>',
-    wantAlines: ['+m'],
-    wantText: ['  word1  word2   word3'],
-  },
-  {
-    description: 'A non-breaking space preceded by a normal space',
-    html: '<html><body> &nbsp;word1 &nbsp;word2 &nbsp;word3<br></body></html>',
-    wantAlines: ['+l'],
-    wantText: ['  word1  word2  word3'],
-  },
-  {
-    description: 'A non-breaking space followed by a normal space',
-    html: '<html><body>&nbsp; word1&nbsp; word2&nbsp; word3<br></body></html>',
-    wantAlines: ['+l'],
-    wantText: ['  word1  word2  word3'],
-  },
-  {
-    description: 'Don\'t collapse spaces that follow a newline',
-    html: '<!doctype html><html><body>something<br>             something<br></body></html>',
-    wantAlines: ['+9', '+m'],
-    wantText: ['something', '             something'],
-  },
-  {
-    description: 'Don\'t collapse spaces that follow a empty paragraph',
-    html: '<!doctype html><html><body>something<p></p>             something<br></body></html>',
-    wantAlines: ['+9', '', '+m'],
-    wantText: ['something', '', '             something'],
-  },
-  {
-    description: 'Don\'t collapse spaces that preceed/follow a newline',
-    html: '<html><body>something            <br>             something<br></body></html>',
-    wantAlines: ['+l', '+m'],
-    wantText: ['something            ', '             something'],
-  },
-  {
-    description: 'Don\'t collapse spaces that preceed/follow a empty paragraph',
-    html: '<html><body>something            <p></p>             something<br></body></html>',
-    wantAlines: ['+l', '', '+m'],
-    wantText: ['something            ', '', '             something'],
-  },
-  {
-    description: 'Don\'t collapse non-breaking spaces that follow a newline',
-    html: '<html><body>something<br>&nbsp;&nbsp;&nbsp;something<br></body></html>',
-    wantAlines: ['+9', '+c'],
-    wantText: ['something', '   something'],
-  },
-  {
-    description: 'Don\'t collapse non-breaking spaces that follow a paragraph',
-    html: '<html><body>something<p></p>&nbsp;&nbsp;&nbsp;something<br></body></html>',
-    wantAlines: ['+9', '', '+c'],
-    wantText: ['something', '', '   something'],
-  },
-  {
-    description: 'Preserve all spaces when multiple are present',
-    html: '<html><body>Need <span> more </span> space<i>  s </i> !<br></body></html>',
-    wantAlines: ['+h*1+4+2'],
-    wantText: ['Need  more  space  s  !'],
-  },
-  {
-    description: 'Newlines and multiple spaces across newlines should be preserved',
-    html: `
-      <html><body>Need
-          <span> more </span>
-          space
-          <i>  s </i>
-          !<br></body></html>`,
-    wantAlines: ['+19*1+4+b'],
-    wantText: ['Need           more           space            s           !'],
-  },
-  {
-    description: 'Multiple new lines at the beginning should be preserved',
-    html: '<html><body><br><br><p></p><p></p>first line<br><br>second line<br></body></html>',
-    wantAlines: ['', '', '', '', '+a', '', '+b'],
-    wantText: ['', '', '', '', 'first line', '', 'second line'],
-  },
-  {
-    description: 'A paragraph with multiple lines should not loose spaces when lines are combined',
-    html: `<html><body><p>
-а б в г ґ д е є ж з и і ї й к л м н о
-п р с т у ф х ц ч ш щ ю я ь</p>
-</body></html>`,
-    wantAlines: ['+1t'],
-    wantText: ['а б в г ґ д е є ж з и і ї й к л м н о п р с т у ф х ц ч ш щ ю я ь'],
-  },
-  {
-    description: 'lines in preformatted text should be kept intact',
-    html: `<html><body><p>
-а б в г ґ д е є ж з и і ї й к л м н о</p><pre>multiple
-lines
-in
-pre
-</pre><p>п р с т у ф х ц ч ш щ ю я
-ь</p>
-</body></html>`,
-    wantAlines: ['+11', '+8', '+5', '+2', '+3', '+r'],
-    wantText: [
-      'а б в г ґ д е є ж з и і ї й к л м н о',
-      'multiple',
-      'lines',
-      'in',
-      'pre',
-      'п р с т у ф х ц ч ш щ ю я ь',
-    ],
-  },
-  {
-    description: 'pre should be on a new line not preceded by a space',
-    html: `<html><body><p>
-    1
-</p><pre>preline
-</pre></body></html>`,
-    wantAlines: ['+6', '+7'],
-    wantText: ['    1 ', 'preline'],
-  },
-  {
-    description: 'Preserve spaces on the beginning and end of a element',
-    html: '<html><body>Need<span> more </span>space<i> s </i>!<br></body></html>',
-    wantAlines: ['+f*1+3+1'],
-    wantText: ['Need more space s !'],
-  },
-  {
-    description: 'Preserve spaces outside elements',
-    html: '<html><body>Need <span>more</span> space <i>s</i> !<br></body></html>',
-    wantAlines: ['+g*1+1+2'],
-    wantText: ['Need more space s !'],
-  },
-  {
-    description: 'Preserve spaces at the end of an element',
-    html: '<html><body>Need <span>more </span>space <i>s </i>!<br></body></html>',
-    wantAlines: ['+g*1+2+1'],
-    wantText: ['Need more space s !'],
-  },
-  {
-    description: 'Preserve spaces at the start of an element',
-    html: '<html><body>Need<span> more</span> space<i> s</i> !<br></body></html>',
-    wantAlines: ['+f*1+2+2'],
-    wantText: ['Need more space s !'],
-  },
-];
-
-describe(__filename, function () {
-  for (const tc of testCases) {
-    describe(tc.description, function () {
-      let apool: APool;
-      let result: {
-        lines: string[],
-        lineAttribs: string[],
-      };
-      if (tc.disabled) {
-        test.skip('If disabled we do not run the test');
-        return;
-      }
-
-      beforeAll(async function () {
-
-        const {window: {document}} = new jsdom.JSDOM(tc.html);
-        apool = new AttributePool();
-        // To reduce test fragility, the attribute pool is seeded with `knownAttribs`, and all
-        // attributes in `tc.wantAlines` must be in `knownAttribs`. (This guarantees that attribute
-        // numbers do not change if the attribute processing code changes.)
-        for (const attrib of knownAttribs) apool.putAttrib(attrib);
-        for (const aline of tc.wantAlines) {
-          for (const op of Changeset.deserializeOps(aline)) {
-            for (const n of attributes.decodeAttribString(op.attribs)) {
-              assert(n < knownAttribs.length);
-            }
-          }
-        }
-        const cc = contentcollector.makeContentCollector(true, null, apool);
-        cc.collectContent(document.body);
-        result = cc.finish();
-        console.log(result);
-      });
-
-      it('text matches', async function () {
-        assert.deepEqual(result.lines, tc.wantText);
-      });
-
-      it('alines match', async function () {
-        assert.deepEqual(result.lineAttribs, tc.wantAlines);
-      });
-
-      it('attributes are sorted in canonical order', async function () {
-        const gotAttribs:string[][][] = [];
-        const wantAttribs = [];
-        for (const aline of result.lineAttribs) {
-          const gotAlineAttribs:string[][] = [];
-          gotAttribs.push(gotAlineAttribs);
-          const wantAlineAttribs:string[] = [];
-          wantAttribs.push(wantAlineAttribs);
-          for (const op of Changeset.deserializeOps(aline)) {
-            const gotOpAttribs:string[] = [...attributes.attribsFromString(op.attribs, apool)];
-            gotAlineAttribs.push(gotOpAttribs);
-            wantAlineAttribs.push(attributes.sort([...gotOpAttribs]));
-          }
-        }
-        assert.deepEqual(gotAttribs, wantAttribs);
-      });
-    });
-  }
-});
diff --git a/src/tests/backend-new/specs/pad_utils.ts b/src/tests/backend-new/specs/pad_utils.ts
index bcccdf449..569f49d04 100644
--- a/src/tests/backend-new/specs/pad_utils.ts
+++ b/src/tests/backend-new/specs/pad_utils.ts
@@ -1,19 +1,19 @@
 import {MapArrayType} from "../../../node/types/MapType";
-const {padutils} = require('../../../static/js/pad_utils');
+import padutils from '../../../static/js/pad_utils';
 import {describe, it, expect, afterEach, beforeAll} from "vitest";
 
 describe(__filename, function () {
   describe('warnDeprecated', function () {
-    const {warnDeprecated} = padutils;
+    const {warnDeprecatedFlags, warnDeprecated} = padutils;
     const backups:MapArrayType<any> = {};
 
     beforeAll(async function () {
-      backups.logger = warnDeprecated.logger;
+      backups.logger = warnDeprecatedFlags.logger;
     });
 
     afterEach(async function () {
-      warnDeprecated.logger = backups.logger;
-      delete warnDeprecated._rl; // Reset internal rate limiter state.
+      warnDeprecatedFlags.logger = backups.logger;
+      delete warnDeprecatedFlags._rl; // Reset internal rate limiter state.
     });
 
     /*it('includes the stack', async function () {
@@ -25,13 +25,13 @@ describe(__filename, function () {
 
     it('rate limited', async function () {
       let got = 0;
-      warnDeprecated.logger = {warn: () => ++got};
+      warnDeprecatedFlags.logger = {warn: () => ++got};
       warnDeprecated(); // Initialize internal rate limiter state.
-      const {period} = warnDeprecated._rl;
+      const {period} = warnDeprecatedFlags._rl!;
       got = 0;
       const testCases = [[0, 1], [0, 1], [period - 1, 1], [period, 2]];
       for (const [now, want] of testCases) { // In a loop so that the stack trace is the same.
-        warnDeprecated._rl.now = () => now;
+        warnDeprecatedFlags._rl!.now = () => now;
         warnDeprecated();
         expect(got).toEqual(want);
       }
diff --git a/src/tests/backend-new/specs/skiplist.ts b/src/tests/backend-new/specs/skiplist.ts
index c1b408e3a..23ad46ae6 100644
--- a/src/tests/backend-new/specs/skiplist.ts
+++ b/src/tests/backend-new/specs/skiplist.ts
@@ -1,12 +1,13 @@
 'use strict';
 
-const SkipList = require('ep_etherpad-lite/static/js/skiplist');
+import SkipList from 'ep_etherpad-lite/static/js/skiplist';
 import {expect, describe, it} from 'vitest';
 
 describe('skiplist.js', function () {
   it('rejects null keys', async function () {
     const skiplist = new SkipList();
     for (const key of [undefined, null]) {
+      // @ts-ignore
       expect(() => skiplist.push({key})).toThrowError();
     }
   });
diff --git a/src/tests/backend/common.ts b/src/tests/backend/common.ts
index 21fb01e2f..4f3937546 100644
--- a/src/tests/backend/common.ts
+++ b/src/tests/backend/common.ts
@@ -2,12 +2,11 @@
 
 import {MapArrayType} from "../../node/types/MapType";
 
-const AttributePool = require('../../static/js/AttributePool');
-const apiHandler = require('../../node/handler/APIHandler');
+import AttributePool from '../../static/js/AttributePool';
 const assert = require('assert').strict;
 const io = require('socket.io-client');
 const log4js = require('log4js');
-const {padutils} = require('../../static/js/pad_utils');
+import padutils from '../../static/js/pad_utils';
 const process = require('process');
 const server = require('../../node/server');
 const setCookieParser = require('set-cookie-parser');
diff --git a/src/tests/backend/specs/ImportEtherpad.ts b/src/tests/backend/specs/ImportEtherpad.ts
index b0a208b4a..b9ac9baaf 100644
--- a/src/tests/backend/specs/ImportEtherpad.ts
+++ b/src/tests/backend/specs/ImportEtherpad.ts
@@ -8,7 +8,7 @@ const db = require('../../../node/db/DB');
 const importEtherpad = require('../../../node/utils/ImportEtherpad');
 const padManager = require('../../../node/db/PadManager');
 const plugins = require('../../../static/js/pluginfw/plugin_defs');
-const {randomString} = require('../../../static/js/pad_utils');
+import {randomString} from '../../../static/js/pad_utils';
 
 describe(__filename, function () {
   let padId: string;
diff --git a/src/tests/backend/specs/chat.ts b/src/tests/backend/specs/chat.ts
index 5070a30a1..62ac97012 100644
--- a/src/tests/backend/specs/chat.ts
+++ b/src/tests/backend/specs/chat.ts
@@ -3,7 +3,7 @@
 import {MapArrayType} from "../../../node/types/MapType";
 import {PluginDef} from "../../../node/types/PartType";
 
-const ChatMessage = require('../../../static/js/ChatMessage');
+import ChatMessage from '../../../static/js/ChatMessage';
 const {Pad} = require('../../../node/db/Pad');
 const assert = require('assert').strict;
 const common = require('../common');
@@ -103,10 +103,14 @@ describe(__filename, function () {
         checkHook('chatNewMessage', ({message}) => {
           assert(message != null);
           assert(message instanceof ChatMessage);
-          assert.equal(message.authorId, authorId);
-          assert.equal(message.text, this.test!.title);
-          assert(message.time >= start);
-          assert(message.time <= Date.now());
+          // @ts-ignore
+          assert.equal(message!.authorId, authorId);
+          // @ts-ignore
+          assert.equal(message!.text, this.test!.title);
+          // @ts-ignore
+          assert(message!.time >= start);
+          // @ts-ignore
+          assert(message!.time <= Date.now());
         }),
         sendChat(socket, {text: this.test!.title}),
       ]);
@@ -153,7 +157,9 @@ describe(__filename, function () {
       const customMetadata = {foo: this.test!.title};
       await Promise.all([
         checkHook('chatNewMessage', ({message}) => {
+          // @ts-ignore
           message.text = modifiedText;
+          // @ts-ignore
           message.customMetadata = customMetadata;
         }),
         (async () => {
diff --git a/src/tests/backend/specs/contentcollector.ts b/src/tests/backend/specs/contentcollector.ts
index 51ae0002f..50178fbae 100644
--- a/src/tests/backend/specs/contentcollector.ts
+++ b/src/tests/backend/specs/contentcollector.ts
@@ -11,16 +11,17 @@
 
 import {APool} from "../../../node/types/PadType";
 
-const AttributePool = require('../../../static/js/AttributePool');
+import AttributePool from '../../../static/js/AttributePool';
 const Changeset = require('../../../static/js/Changeset');
 const assert = require('assert').strict;
-const attributes = require('../../../static/js/attributes');
+import attributes from '../../../static/js/attributes';
 const contentcollector = require('../../../static/js/contentcollector');
-const jsdom = require('jsdom');
+import jsdom from 'jsdom';
+import {Attribute} from "../../../static/js/types/Attribute";
 
 // All test case `wantAlines` values must only refer to attributes in this list so that the
 // attribute numbers do not change due to changes in pool insertion order.
-const knownAttribs = [
+const knownAttribs: Attribute[] = [
   ['insertorder', 'first'],
   ['italic', 'true'],
   ['list', 'bullet1'],
@@ -336,7 +337,7 @@ pre
 describe(__filename, function () {
   for (const tc of testCases) {
     describe(tc.description, function () {
-      let apool: APool;
+      let apool: AttributePool;
       let result: {
         lines: string[],
         lineAttribs: string[],
@@ -376,11 +377,12 @@ describe(__filename, function () {
         for (const aline of result.lineAttribs) {
           const gotAlineAttribs:string[][] = [];
           gotAttribs.push(gotAlineAttribs);
-          const wantAlineAttribs:string[] = [];
+          const wantAlineAttribs:Attribute[] = [];
           wantAttribs.push(wantAlineAttribs);
           for (const op of Changeset.deserializeOps(aline)) {
-            const gotOpAttribs:string[] = [...attributes.attribsFromString(op.attribs, apool)];
+            const gotOpAttribs = [...attributes.attribsFromString(op.attribs, apool)] as unknown as Attribute;
             gotAlineAttribs.push(gotOpAttribs);
+            // @ts-ignore
             wantAlineAttribs.push(attributes.sort([...gotOpAttribs]));
           }
         }