diff --git a/dev/build/esbuild.js b/dev/build/esbuild.js
index fea8c01e3..cd8bf279f 100644
--- a/dev/build/esbuild.js
+++ b/dev/build/esbuild.js
@@ -10,7 +10,7 @@ const isProd = process.argv[2] === 'production';
 
 // Gather our input files
 const entryPoints = {
-    app: path.join(__dirname, '../../resources/js/app.js'),
+    app: path.join(__dirname, '../../resources/js/app.ts'),
     code: path.join(__dirname, '../../resources/js/code/index.mjs'),
     'legacy-modes': path.join(__dirname, '../../resources/js/code/legacy-modes.mjs'),
     markdown: path.join(__dirname, '../../resources/js/markdown/index.mjs'),
diff --git a/resources/js/components/add-remove-rows.js b/resources/js/components/add-remove-rows.js
index 488654279..e7de15ae5 100644
--- a/resources/js/components/add-remove-rows.js
+++ b/resources/js/components/add-remove-rows.js
@@ -1,4 +1,4 @@
-import {onChildEvent} from '../services/dom';
+import {onChildEvent} from '../services/dom.ts';
 import {uniqueId} from '../services/util.ts';
 import {Component} from './component';
 
diff --git a/resources/js/components/ajax-delete-row.js b/resources/js/components/ajax-delete-row.js
index aa2801f19..6ed3deedf 100644
--- a/resources/js/components/ajax-delete-row.js
+++ b/resources/js/components/ajax-delete-row.js
@@ -1,4 +1,4 @@
-import {onSelect} from '../services/dom';
+import {onSelect} from '../services/dom.ts';
 import {Component} from './component';
 
 export class AjaxDeleteRow extends Component {
diff --git a/resources/js/components/ajax-form.js b/resources/js/components/ajax-form.js
index 583dde572..de1a6db43 100644
--- a/resources/js/components/ajax-form.js
+++ b/resources/js/components/ajax-form.js
@@ -1,4 +1,4 @@
-import {onEnterPress, onSelect} from '../services/dom';
+import {onEnterPress, onSelect} from '../services/dom.ts';
 import {Component} from './component';
 
 /**
diff --git a/resources/js/components/attachments.js b/resources/js/components/attachments.js
index f45b25e36..2dc7313a8 100644
--- a/resources/js/components/attachments.js
+++ b/resources/js/components/attachments.js
@@ -1,4 +1,4 @@
-import {showLoading} from '../services/dom';
+import {showLoading} from '../services/dom.ts';
 import {Component} from './component';
 
 export class Attachments extends Component {
diff --git a/resources/js/components/auto-suggest.js b/resources/js/components/auto-suggest.js
index 07711312f..0b828e71b 100644
--- a/resources/js/components/auto-suggest.js
+++ b/resources/js/components/auto-suggest.js
@@ -1,7 +1,7 @@
 import {escapeHtml} from '../services/util.ts';
-import {onChildEvent} from '../services/dom';
+import {onChildEvent} from '../services/dom.ts';
 import {Component} from './component';
-import {KeyboardNavigationHandler} from '../services/keyboard-navigation';
+import {KeyboardNavigationHandler} from '../services/keyboard-navigation.ts';
 
 const ajaxCache = {};
 
diff --git a/resources/js/components/book-sort.js b/resources/js/components/book-sort.js
index 2ba7d5d36..48557141f 100644
--- a/resources/js/components/book-sort.js
+++ b/resources/js/components/book-sort.js
@@ -1,6 +1,6 @@
 import Sortable, {MultiDrag} from 'sortablejs';
 import {Component} from './component';
-import {htmlToDom} from '../services/dom';
+import {htmlToDom} from '../services/dom.ts';
 
 // Auto sort control
 const sortOperations = {
diff --git a/resources/js/components/code-editor.js b/resources/js/components/code-editor.js
index 091c3483f..12937d472 100644
--- a/resources/js/components/code-editor.js
+++ b/resources/js/components/code-editor.js
@@ -1,4 +1,4 @@
-import {onChildEvent, onEnterPress, onSelect} from '../services/dom';
+import {onChildEvent, onEnterPress, onSelect} from '../services/dom.ts';
 import {Component} from './component';
 
 export class CodeEditor extends Component {
diff --git a/resources/js/components/confirm-dialog.js b/resources/js/components/confirm-dialog.js
index 184618fcc..00f3cfed2 100644
--- a/resources/js/components/confirm-dialog.js
+++ b/resources/js/components/confirm-dialog.js
@@ -1,4 +1,4 @@
-import {onSelect} from '../services/dom';
+import {onSelect} from '../services/dom.ts';
 import {Component} from './component';
 
 /**
diff --git a/resources/js/components/dropdown.js b/resources/js/components/dropdown.js
index 4efd428ac..5dd5dd93b 100644
--- a/resources/js/components/dropdown.js
+++ b/resources/js/components/dropdown.js
@@ -1,5 +1,5 @@
-import {onSelect} from '../services/dom';
-import {KeyboardNavigationHandler} from '../services/keyboard-navigation';
+import {onSelect} from '../services/dom.ts';
+import {KeyboardNavigationHandler} from '../services/keyboard-navigation.ts';
 import {Component} from './component';
 
 /**
diff --git a/resources/js/components/dropzone.js b/resources/js/components/dropzone.js
index 920fe875f..598e0d8d4 100644
--- a/resources/js/components/dropzone.js
+++ b/resources/js/components/dropzone.js
@@ -2,7 +2,7 @@ import {Component} from './component';
 import {Clipboard} from '../services/clipboard.ts';
 import {
     elem, getLoading, onSelect, removeLoading,
-} from '../services/dom';
+} from '../services/dom.ts';
 
 export class Dropzone extends Component {
 
diff --git a/resources/js/components/entity-permissions.js b/resources/js/components/entity-permissions.js
index 7ab99a2a7..b020c5d85 100644
--- a/resources/js/components/entity-permissions.js
+++ b/resources/js/components/entity-permissions.js
@@ -1,4 +1,4 @@
-import {htmlToDom} from '../services/dom';
+import {htmlToDom} from '../services/dom.ts';
 import {Component} from './component';
 
 export class EntityPermissions extends Component {
diff --git a/resources/js/components/entity-search.js b/resources/js/components/entity-search.js
index 7a5044470..9d4513326 100644
--- a/resources/js/components/entity-search.js
+++ b/resources/js/components/entity-search.js
@@ -1,4 +1,4 @@
-import {onSelect} from '../services/dom';
+import {onSelect} from '../services/dom.ts';
 import {Component} from './component';
 
 export class EntitySearch extends Component {
diff --git a/resources/js/components/entity-selector.js b/resources/js/components/entity-selector.js
index 561370d7a..7491119a1 100644
--- a/resources/js/components/entity-selector.js
+++ b/resources/js/components/entity-selector.js
@@ -1,4 +1,4 @@
-import {onChildEvent} from '../services/dom';
+import {onChildEvent} from '../services/dom.ts';
 import {Component} from './component';
 
 /**
diff --git a/resources/js/components/event-emit-select.js b/resources/js/components/event-emit-select.js
index 2097c0528..f722a25e7 100644
--- a/resources/js/components/event-emit-select.js
+++ b/resources/js/components/event-emit-select.js
@@ -1,4 +1,4 @@
-import {onSelect} from '../services/dom';
+import {onSelect} from '../services/dom.ts';
 import {Component} from './component';
 
 /**
diff --git a/resources/js/components/global-search.js b/resources/js/components/global-search.js
index 44c0d02f9..2cdaf591a 100644
--- a/resources/js/components/global-search.js
+++ b/resources/js/components/global-search.js
@@ -1,6 +1,6 @@
-import {htmlToDom} from '../services/dom';
+import {htmlToDom} from '../services/dom.ts';
 import {debounce} from '../services/util.ts';
-import {KeyboardNavigationHandler} from '../services/keyboard-navigation';
+import {KeyboardNavigationHandler} from '../services/keyboard-navigation.ts';
 import {Component} from './component';
 
 /**
diff --git a/resources/js/components/image-manager.js b/resources/js/components/image-manager.js
index 47231477b..c8108ab28 100644
--- a/resources/js/components/image-manager.js
+++ b/resources/js/components/image-manager.js
@@ -1,6 +1,6 @@
 import {
     onChildEvent, onSelect, removeLoading, showLoading,
-} from '../services/dom';
+} from '../services/dom.ts';
 import {Component} from './component';
 
 export class ImageManager extends Component {
diff --git a/resources/js/components/optional-input.js b/resources/js/components/optional-input.js
index 64cee12cd..1b133047d 100644
--- a/resources/js/components/optional-input.js
+++ b/resources/js/components/optional-input.js
@@ -1,4 +1,4 @@
-import {onSelect} from '../services/dom';
+import {onSelect} from '../services/dom.ts';
 import {Component} from './component';
 
 export class OptionalInput extends Component {
diff --git a/resources/js/components/page-comment.js b/resources/js/components/page-comment.js
index fd8ad1f2e..8c0a8b33e 100644
--- a/resources/js/components/page-comment.js
+++ b/resources/js/components/page-comment.js
@@ -1,5 +1,5 @@
 import {Component} from './component';
-import {getLoading, htmlToDom} from '../services/dom';
+import {getLoading, htmlToDom} from '../services/dom.ts';
 import {buildForInput} from '../wysiwyg-tinymce/config';
 
 export class PageComment extends Component {
diff --git a/resources/js/components/page-comments.js b/resources/js/components/page-comments.js
index 1d6abfe20..3d7e1365f 100644
--- a/resources/js/components/page-comments.js
+++ b/resources/js/components/page-comments.js
@@ -1,5 +1,5 @@
 import {Component} from './component';
-import {getLoading, htmlToDom} from '../services/dom';
+import {getLoading, htmlToDom} from '../services/dom.ts';
 import {buildForInput} from '../wysiwyg-tinymce/config';
 
 export class PageComments extends Component {
diff --git a/resources/js/components/page-display.js b/resources/js/components/page-display.js
index ff9d68c7a..d3ac78a4a 100644
--- a/resources/js/components/page-display.js
+++ b/resources/js/components/page-display.js
@@ -1,4 +1,4 @@
-import * as DOM from '../services/dom';
+import * as DOM from '../services/dom.ts';
 import {scrollAndHighlightElement} from '../services/util.ts';
 import {Component} from './component';
 
diff --git a/resources/js/components/page-editor.js b/resources/js/components/page-editor.js
index 9450444ca..7ffceb0f9 100644
--- a/resources/js/components/page-editor.js
+++ b/resources/js/components/page-editor.js
@@ -1,4 +1,4 @@
-import {onSelect} from '../services/dom';
+import {onSelect} from '../services/dom.ts';
 import {debounce} from '../services/util.ts';
 import {Component} from './component';
 import {utcTimeStampToLocalTime} from '../services/dates.ts';
diff --git a/resources/js/components/pointer.js b/resources/js/components/pointer.js
index 607576cb9..292b923e5 100644
--- a/resources/js/components/pointer.js
+++ b/resources/js/components/pointer.js
@@ -1,4 +1,4 @@
-import * as DOM from '../services/dom';
+import * as DOM from '../services/dom.ts';
 import {Component} from './component';
 import {copyTextToClipboard} from '../services/clipboard.ts';
 
diff --git a/resources/js/components/popup.js b/resources/js/components/popup.js
index edd428037..6bd8f9c72 100644
--- a/resources/js/components/popup.js
+++ b/resources/js/components/popup.js
@@ -1,5 +1,5 @@
 import {fadeIn, fadeOut} from '../services/animations.ts';
-import {onSelect} from '../services/dom';
+import {onSelect} from '../services/dom.ts';
 import {Component} from './component';
 
 /**
diff --git a/resources/js/components/template-manager.js b/resources/js/components/template-manager.js
index 56ec876d4..cf81990ab 100644
--- a/resources/js/components/template-manager.js
+++ b/resources/js/components/template-manager.js
@@ -1,4 +1,4 @@
-import * as DOM from '../services/dom';
+import * as DOM from '../services/dom.ts';
 import {Component} from './component';
 
 export class TemplateManager extends Component {
diff --git a/resources/js/components/user-select.js b/resources/js/components/user-select.js
index e6adc3c23..f9ec03ed3 100644
--- a/resources/js/components/user-select.js
+++ b/resources/js/components/user-select.js
@@ -1,4 +1,4 @@
-import {onChildEvent} from '../services/dom';
+import {onChildEvent} from '../services/dom.ts';
 import {Component} from './component';
 
 export class UserSelect extends Component {
diff --git a/resources/js/services/dom.js b/resources/js/services/dom.ts
similarity index 63%
rename from resources/js/services/dom.js
rename to resources/js/services/dom.ts
index bcfd0b565..c88827bac 100644
--- a/resources/js/services/dom.js
+++ b/resources/js/services/dom.ts
@@ -1,12 +1,15 @@
+/**
+ * Check if the given param is a HTMLElement
+ */
+export function isHTMLElement(el: any): el is HTMLElement {
+    return el instanceof HTMLElement;
+}
+
 /**
  * Create a new element with the given attrs and children.
  * Children can be a string for text nodes or other elements.
- * @param {String} tagName
- * @param {Object<String, String>} attrs
- * @param {Element[]|String[]}children
- * @return {*}
  */
-export function elem(tagName, attrs = {}, children = []) {
+export function elem(tagName: string, attrs: Record<string, string> = {}, children: Element[]|string[] = []): HTMLElement {
     const el = document.createElement(tagName);
 
     for (const [key, val] of Object.entries(attrs)) {
@@ -30,10 +33,8 @@ export function elem(tagName, attrs = {}, children = []) {
 
 /**
  * Run the given callback against each element that matches the given selector.
- * @param {String} selector
- * @param {Function<Element>} callback
  */
-export function forEach(selector, callback) {
+export function forEach(selector: string, callback: (el: Element) => any) {
     const elements = document.querySelectorAll(selector);
     for (const element of elements) {
         callback(element);
@@ -42,11 +43,8 @@ export function forEach(selector, callback) {
 
 /**
  * Helper to listen to multiple DOM events
- * @param {Element} listenerElement
- * @param {Array<String>} events
- * @param {Function<Event>} callback
  */
-export function onEvents(listenerElement, events, callback) {
+export function onEvents(listenerElement: Element, events: string[], callback: (e: Event) => any): void {
     for (const eventName of events) {
         listenerElement.addEventListener(eventName, callback);
     }
@@ -55,10 +53,8 @@ export function onEvents(listenerElement, events, callback) {
 /**
  * Helper to run an action when an element is selected.
  * A "select" is made to be accessible, So can be a click, space-press or enter-press.
- * @param {HTMLElement|Array} elements
- * @param {function} callback
  */
-export function onSelect(elements, callback) {
+export function onSelect(elements: HTMLElement|HTMLElement[], callback: (e: Event) => any): void {
     if (!Array.isArray(elements)) {
         elements = [elements];
     }
@@ -76,16 +72,13 @@ export function onSelect(elements, callback) {
 
 /**
  * Listen to key press on the given element(s).
- * @param {String} key
- * @param {HTMLElement|Array} elements
- * @param {function} callback
  */
-function onKeyPress(key, elements, callback) {
+function onKeyPress(key: string, elements: HTMLElement|HTMLElement[], callback: (e: KeyboardEvent) => any): void {
     if (!Array.isArray(elements)) {
         elements = [elements];
     }
 
-    const listener = event => {
+    const listener = (event: KeyboardEvent) => {
         if (event.key === key) {
             callback(event);
         }
@@ -96,19 +89,15 @@ function onKeyPress(key, elements, callback) {
 
 /**
  * Listen to enter press on the given element(s).
- * @param {HTMLElement|Array} elements
- * @param {function} callback
  */
-export function onEnterPress(elements, callback) {
+export function onEnterPress(elements: HTMLElement|HTMLElement[], callback: (e: KeyboardEvent) => any): void {
     onKeyPress('Enter', elements, callback);
 }
 
 /**
  * Listen to escape press on the given element(s).
- * @param {HTMLElement|Array} elements
- * @param {function} callback
  */
-export function onEscapePress(elements, callback) {
+export function onEscapePress(elements: HTMLElement|HTMLElement[], callback: (e: KeyboardEvent) => any): void {
     onKeyPress('Escape', elements, callback);
 }
 
@@ -116,14 +105,15 @@ export function onEscapePress(elements, callback) {
  * Set a listener on an element for an event emitted by a child
  * matching the given childSelector param.
  * Used in a similar fashion to jQuery's $('listener').on('eventName', 'childSelector', callback)
- * @param {Element} listenerElement
- * @param {String} childSelector
- * @param {String} eventName
- * @param {Function} callback
  */
-export function onChildEvent(listenerElement, childSelector, eventName, callback) {
-    listenerElement.addEventListener(eventName, event => {
-        const matchingChild = event.target.closest(childSelector);
+export function onChildEvent(
+    listenerElement: HTMLElement,
+    childSelector: string,
+    eventName: string,
+    callback: (this: HTMLElement, e: Event, child: HTMLElement) => any
+): void {
+    listenerElement.addEventListener(eventName, (event: Event) => {
+        const matchingChild = (event.target as HTMLElement|null)?.closest(childSelector) as HTMLElement;
         if (matchingChild) {
             callback.call(matchingChild, event, matchingChild);
         }
@@ -132,16 +122,13 @@ export function onChildEvent(listenerElement, childSelector, eventName, callback
 
 /**
  * Look for elements that match the given selector and contain the given text.
- * Is case insensitive and returns the first result or null if nothing is found.
- * @param {String} selector
- * @param {String} text
- * @returns {Element}
+ * Is case-insensitive and returns the first result or null if nothing is found.
  */
-export function findText(selector, text) {
+export function findText(selector: string, text: string): Element|null {
     const elements = document.querySelectorAll(selector);
     text = text.toLowerCase();
     for (const element of elements) {
-        if (element.textContent.toLowerCase().includes(text)) {
+        if ((element.textContent || '').toLowerCase().includes(text) && isHTMLElement(element)) {
             return element;
         }
     }
@@ -151,17 +138,15 @@ export function findText(selector, text) {
 /**
  * Show a loading indicator in the given element.
  * This will effectively clear the element.
- * @param {Element} element
  */
-export function showLoading(element) {
+export function showLoading(element: HTMLElement): void {
     element.innerHTML = '<div class="loading-container"><div></div><div></div><div></div></div>';
 }
 
 /**
  * Get a loading element indicator element.
- * @returns {Element}
  */
-export function getLoading() {
+export function getLoading(): HTMLElement {
     const wrap = document.createElement('div');
     wrap.classList.add('loading-container');
     wrap.innerHTML = '<div></div><div></div><div></div>';
@@ -170,9 +155,8 @@ export function getLoading() {
 
 /**
  * Remove any loading indicators within the given element.
- * @param {Element} element
  */
-export function removeLoading(element) {
+export function removeLoading(element: HTMLElement): void {
     const loadingEls = element.querySelectorAll('.loading-container');
     for (const el of loadingEls) {
         el.remove();
@@ -182,12 +166,15 @@ export function removeLoading(element) {
 /**
  * Convert the given html data into a live DOM element.
  * Initiates any components defined in the data.
- * @param {String} html
- * @returns {Element}
  */
-export function htmlToDom(html) {
+export function htmlToDom(html: string): HTMLElement {
     const wrap = document.createElement('div');
     wrap.innerHTML = html;
     window.$components.init(wrap);
-    return wrap.children[0];
+    const firstChild = wrap.children[0];
+    if (!isHTMLElement(firstChild)) {
+        throw new Error('Could not find child HTMLElement when creating DOM element from HTML');
+    }
+
+    return firstChild;
 }
diff --git a/resources/js/services/keyboard-navigation.js b/resources/js/services/keyboard-navigation.ts
similarity index 66%
rename from resources/js/services/keyboard-navigation.js
rename to resources/js/services/keyboard-navigation.ts
index 34111bb2d..13fbdfecc 100644
--- a/resources/js/services/keyboard-navigation.js
+++ b/resources/js/services/keyboard-navigation.ts
@@ -1,14 +1,17 @@
+import {isHTMLElement} from "./dom";
+
+type OptionalKeyEventHandler = ((e: KeyboardEvent) => any)|null;
+
 /**
  * Handle common keyboard navigation events within a given container.
  */
 export class KeyboardNavigationHandler {
 
-    /**
-     * @param {Element} container
-     * @param {Function|null} onEscape
-     * @param {Function|null} onEnter
-     */
-    constructor(container, onEscape = null, onEnter = null) {
+    protected containers: HTMLElement[];
+    protected onEscape: OptionalKeyEventHandler;
+    protected onEnter: OptionalKeyEventHandler;
+
+    constructor(container: HTMLElement, onEscape: OptionalKeyEventHandler = null, onEnter: OptionalKeyEventHandler = null) {
         this.containers = [container];
         this.onEscape = onEscape;
         this.onEnter = onEnter;
@@ -18,9 +21,8 @@ export class KeyboardNavigationHandler {
     /**
      * Also share the keyboard event handling to the given element.
      * Only elements within the original container are considered focusable though.
-     * @param {Element} element
      */
-    shareHandlingToEl(element) {
+    shareHandlingToEl(element: HTMLElement) {
         this.containers.push(element);
         element.addEventListener('keydown', this.#keydownHandler.bind(this));
     }
@@ -30,7 +32,8 @@ export class KeyboardNavigationHandler {
      */
     focusNext() {
         const focusable = this.#getFocusable();
-        const currentIndex = focusable.indexOf(document.activeElement);
+        const activeEl = document.activeElement;
+        const currentIndex = isHTMLElement(activeEl) ? focusable.indexOf(activeEl) : -1;
         let newIndex = currentIndex + 1;
         if (newIndex >= focusable.length) {
             newIndex = 0;
@@ -44,7 +47,8 @@ export class KeyboardNavigationHandler {
      */
     focusPrevious() {
         const focusable = this.#getFocusable();
-        const currentIndex = focusable.indexOf(document.activeElement);
+        const activeEl = document.activeElement;
+        const currentIndex = isHTMLElement(activeEl) ? focusable.indexOf(activeEl) : -1;
         let newIndex = currentIndex - 1;
         if (newIndex < 0) {
             newIndex = focusable.length - 1;
@@ -53,12 +57,9 @@ export class KeyboardNavigationHandler {
         focusable[newIndex].focus();
     }
 
-    /**
-     * @param {KeyboardEvent} event
-     */
-    #keydownHandler(event) {
+    #keydownHandler(event: KeyboardEvent) {
         // Ignore certain key events in inputs to allow text editing.
-        if (event.target.matches('input') && (event.key === 'ArrowRight' || event.key === 'ArrowLeft')) {
+        if (isHTMLElement(event.target) && event.target.matches('input') && (event.key === 'ArrowRight' || event.key === 'ArrowLeft')) {
             return;
         }
 
@@ -71,7 +72,7 @@ export class KeyboardNavigationHandler {
         } else if (event.key === 'Escape') {
             if (this.onEscape) {
                 this.onEscape(event);
-            } else if (document.activeElement) {
+            } else if (isHTMLElement(document.activeElement)) {
                 document.activeElement.blur();
             }
         } else if (event.key === 'Enter' && this.onEnter) {
@@ -81,14 +82,15 @@ export class KeyboardNavigationHandler {
 
     /**
      * Get an array of focusable elements within the current containers.
-     * @returns {Element[]}
      */
-    #getFocusable() {
-        const focusable = [];
+    #getFocusable(): HTMLElement[] {
+        const focusable: HTMLElement[] = [];
         const selector = '[tabindex]:not([tabindex="-1"]),[href],button:not([tabindex="-1"],[disabled]),input:not([type=hidden])';
         for (const container of this.containers) {
-            focusable.push(...container.querySelectorAll(selector));
+            const toAdd = [...container.querySelectorAll(selector)].filter(e => isHTMLElement(e));
+            focusable.push(...toAdd);
         }
+
         return focusable;
     }