diff --git a/app/javascript/.eslintrc.js b/app/javascript/.eslintrc.js
index 53d5898fa..411f7f23f 100644
--- a/app/javascript/.eslintrc.js
+++ b/app/javascript/.eslintrc.js
@@ -54,6 +54,7 @@ module.exports = {
     ],
     'react/jsx-no-target-blank': [2, { enforceDynamicLinks: 'always' }],
     'jsx-a11y/no-onchange': 'off',
+    'prefer-const': ['error'],
   },
   overrides: [
     {
diff --git a/app/javascript/admin/controllers/ahoy_controller.js b/app/javascript/admin/controllers/ahoy_controller.js
index ec246dbf5..4811cd4a4 100644
--- a/app/javascript/admin/controllers/ahoy_controller.js
+++ b/app/javascript/admin/controllers/ahoy_controller.js
@@ -9,7 +9,7 @@ ahoy.configure({
 export default class AhoyController extends Controller {
   trackOverviewLink(event) {
     event.preventDefault();
-    let properties = {
+    const properties = {
       action: event.type,
       target: event.target.toString(),
     };
diff --git a/app/javascript/admin/controllers/data_update_script_controller.js b/app/javascript/admin/controllers/data_update_script_controller.js
index bb2e87229..5ff00f885 100644
--- a/app/javascript/admin/controllers/data_update_script_controller.js
+++ b/app/javascript/admin/controllers/data_update_script_controller.js
@@ -4,10 +4,10 @@ export default class DataUpdateScriptController extends Controller {
   forceRun(event) {
     event.preventDefault();
     const id = event.target.dataset.value;
-    let statusColumn = document.getElementById(
+    const statusColumn = document.getElementById(
       `data_update_script_${id}_status`,
     );
-    let runAtColumn = document.getElementById(
+    const runAtColumn = document.getElementById(
       `data_update_script_${id}_run_at`,
     );
 
@@ -47,7 +47,7 @@ export default class DataUpdateScriptController extends Controller {
 
   pollForScriptResponse(id, statusColumn, runAtColumn) {
     let counter = 0;
-    let pollForStatus = setInterval(() => {
+    const pollForStatus = setInterval(() => {
       counter++;
       this.checkForUpdatedDataScript(id, runAtColumn, statusColumn).then(
         (updatedDataScript) => {
@@ -60,12 +60,12 @@ export default class DataUpdateScriptController extends Controller {
               if (updatedDataScript.error) {
                 // we need to show the html as text instead of a parsed version,
                 // hence we manipulate the DOM through this longer process.
-                let errorElem = document.createElement('div');
+                const errorElem = document.createElement('div');
                 errorElem.setAttribute('class', 'fs-xs');
                 errorElem.setAttribute('id', `data_update_script_${id}_error`);
                 statusColumn.appendChild(errorElem);
 
-                let completedErrorElem = document.getElementById(
+                const completedErrorElem = document.getElementById(
                   `data_update_script_${id}_error`,
                 );
                 completedErrorElem.innerText = updatedDataScript.error;
@@ -114,7 +114,7 @@ export default class DataUpdateScriptController extends Controller {
     }).then((response) => {
       if (response.ok) {
         return response.json().then((json) => {
-          let script = json.response;
+          const script = json.response;
           if (script.status === 'succeeded' || script.status === 'failed') {
             return script;
           }
@@ -134,7 +134,7 @@ export default class DataUpdateScriptController extends Controller {
   }
 
   setErrorBanner(runAtColumn, statusColumn, error, bannerClass) {
-    let classList = document.getElementsByClassName(
+    const classList = document.getElementsByClassName(
       'data-update-script__alert',
     )[0].classList;
 
diff --git a/app/javascript/admin/controllers/image_upload_controller.js b/app/javascript/admin/controllers/image_upload_controller.js
index 4118aa75e..67fb2b025 100644
--- a/app/javascript/admin/controllers/image_upload_controller.js
+++ b/app/javascript/admin/controllers/image_upload_controller.js
@@ -9,7 +9,7 @@ export default class ImageUploadController extends Controller {
 
     const token = document.getElementsByName('authenticity_token')[0].value;
     const image = this.fileFieldTarget.files[0];
-    let formData = new FormData();
+    const formData = new FormData();
 
     formData.append('authenticity_token', token);
     formData.append('image', image);
diff --git a/app/javascript/chat/chat.jsx b/app/javascript/chat/chat.jsx
index a083a1879..ebbc4cb29 100644
--- a/app/javascript/chat/chat.jsx
+++ b/app/javascript/chat/chat.jsx
@@ -194,7 +194,7 @@ export class Chat extends Component {
     getChannelRequestInfo().then((response) => {
       const { result } = response;
       const { user_joining_requests, channel_joining_memberships } = result;
-      let totalRequest =
+      const totalRequest =
         user_joining_requests?.length + channel_joining_memberships?.length;
       this.setState({
         userRequestCount: totalRequest,
@@ -811,7 +811,7 @@ export class Chat extends Component {
       newUnopenedChannelIds.splice(index, 1);
     }
 
-    let updatedActiveChannel = this.filterForActiveChannel(
+    const updatedActiveChannel = this.filterForActiveChannel(
       channelList,
       id,
       currentUserId,
@@ -1251,8 +1251,8 @@ export class Chat extends Component {
       const { notificationsPermission } = state;
       const notificationsButton = '';
       let notificationsState = '';
-      let invitesButton = '';
-      let joiningRequestButton = '';
+      const invitesButton = '';
+      const joiningRequestButton = '';
       if (notificationsPermission === 'granted') {
         notificationsState = (
           <div className="chat_chatconfig chat_chatconfig--on">
diff --git a/app/javascript/packs/dashboardTagsDisableUnchangedButtons.js b/app/javascript/packs/dashboardTagsDisableUnchangedButtons.js
index 0a85f47a0..45ff28bc0 100644
--- a/app/javascript/packs/dashboardTagsDisableUnchangedButtons.js
+++ b/app/javascript/packs/dashboardTagsDisableUnchangedButtons.js
@@ -1,35 +1,36 @@
-document.getElementById('follows_update_form').addEventListener('submit', checkChanged);
+document
+  .getElementById('follows_update_form')
+  .addEventListener('submit', checkChanged);
 
-document.addEventListener('change', function(event) {
-  if (event.target && event.target.name == 'follows[][explicit_points]'){
-    addChanged(event.target)
+document.addEventListener('change', (event) => {
+  if (event.target && event.target.name == 'follows[][explicit_points]') {
+    addChanged(event.target);
   }
 });
 
 function addChanged(element) {
   element.setAttribute('changed', true);
-};
+}
 
 function checkChanged(event) {
   if (document.querySelector('input[changed]')) {
     disableAllUnchanged();
-  }
-  else {
+  } else {
     event.preventDefault();
   }
-};
+}
 
 function disableAllUnchanged() {
-  document.querySelectorAll('div[id^="follows"]').forEach(disableUnchanged)
-};
+  document.querySelectorAll('div[id^="follows"]').forEach(disableUnchanged);
+}
 
 function disableUnchanged(item) {
-  let inputs = item.getElementsByTagName('input')
-  let id = inputs[0]
-  let point = inputs[1]
+  const inputs = item.getElementsByTagName('input');
+  const id = inputs[0];
+  const point = inputs[1];
 
   if (!point.hasAttribute('changed')) {
-    point.setAttribute('disabled', true)
-    id.setAttribute('disabled', true)
+    point.setAttribute('disabled', true);
+    id.setAttribute('disabled', true);
   }
-};
+}
diff --git a/app/javascript/shared/components/useKeyboardShortcuts.js b/app/javascript/shared/components/useKeyboardShortcuts.js
index fa7923353..8ac2c32f0 100644
--- a/app/javascript/shared/components/useKeyboardShortcuts.js
+++ b/app/javascript/shared/components/useKeyboardShortcuts.js
@@ -100,9 +100,8 @@ export function useKeyboardShortcuts(
   // Set up key chains
   useEffect(() => {
     if (!keyChainQueue && keyChain.length === 0) return;
-    let timeout;
 
-    timeout = window.setTimeout(() => {
+    const timeout = window.setTimeout(() => {
       clearTimeout(timeout);
       setKeyChain([]);
     }, mergedOptions.timeout);
diff --git a/app/javascript/topNavigation/utilities.js b/app/javascript/topNavigation/utilities.js
index 58c682110..007f3c5de 100644
--- a/app/javascript/topNavigation/utilities.js
+++ b/app/javascript/topNavigation/utilities.js
@@ -23,7 +23,7 @@ function toggleHeaderMenu(memberMenu, navigationButton) {
     return;
   }
 
-  let crayonsHeaderMenuClassList = memberMenu.classList;
+  const crayonsHeaderMenuClassList = memberMenu.classList;
   if (crayonsHeaderMenuClassList.contains('showing')) {
     crayonsHeaderMenuClassList.remove('showing');
     navigationButton.setAttribute('aria-expanded', 'false');
@@ -31,7 +31,7 @@ function toggleHeaderMenu(memberMenu, navigationButton) {
     crayonsHeaderMenuClassList.add('showing');
     navigationButton.setAttribute('aria-expanded', 'true');
 
-    let firstNavLink = document.getElementById('first-nav-link');
+    const firstNavLink = document.getElementById('first-nav-link');
     if (firstNavLink) {
       setTimeout(() => {
         // focus first item on open
@@ -53,7 +53,7 @@ export function initializeTouchDevice(memberTopMenu, menuNavButton) {
   }
 
   if (memberTopMenu) {
-    let crayonsHeaderMenuClassList = memberTopMenu.classList;
+    const crayonsHeaderMenuClassList = memberTopMenu.classList;
 
     setTimeout(() => {
       closeHeaderMenu(memberTopMenu, menuNavButton);
diff --git a/app/javascript/utilities/codeFullscreenModeSwitcher.js b/app/javascript/utilities/codeFullscreenModeSwitcher.js
index 9f578264d..4bcef2742 100644
--- a/app/javascript/utilities/codeFullscreenModeSwitcher.js
+++ b/app/javascript/utilities/codeFullscreenModeSwitcher.js
@@ -37,7 +37,7 @@ function toggleOverflowForDocument(overflow) {
 
 export function addFullScreenModeControl(elements) {
   if (elements) {
-    for (let element of elements) {
+    for (const element of elements) {
       element.addEventListener('click', fullScreenModeControl);
     }
   }
@@ -45,7 +45,7 @@ export function addFullScreenModeControl(elements) {
 
 function removeFullScreenModeControl(elements) {
   if (elements) {
-    for (let element of elements) {
+    for (const element of elements) {
       element.removeEventListener('click', fullScreenModeControl);
     }
   }
diff --git a/cypress/.eslintrc.js b/cypress/.eslintrc.js
index 6b42f8074..ef03accab 100644
--- a/cypress/.eslintrc.js
+++ b/cypress/.eslintrc.js
@@ -17,6 +17,7 @@ module.exports = {
     'import/order': ['error'],
     'import/prefer-default-export': 'off',
     'no-unused-vars': ['error', { argsIgnorePattern: '^_' }],
+    'prefer-const': ['error'],
   },
   overrides: [
     {