diff --git a/assets/js/notifications.js b/assets/js/notifications.ts
similarity index 54%
rename from assets/js/notifications.js
rename to assets/js/notifications.ts
index 02167858..6ae7ee4a 100644
--- a/assets/js/notifications.js
+++ b/assets/js/notifications.ts
@@ -5,20 +5,17 @@
 import { fetchJson, handleError } from './utils/requests';
 import { $ } from './utils/dom';
 import { delegate } from './utils/events';
-import { assertNotNull } from './utils/assert';
+import { assertNotNull, assertNotUndefined } from './utils/assert';
 import store from './utils/store';
 
 const NOTIFICATION_INTERVAL = 600000,
       NOTIFICATION_EXPIRES = 300000;
 
-function makeRequest(verb) {
-  return fetchJson(verb, '/notifications/unread').then(handleError);
-}
-
 function bindSubscriptionLinks() {
   delegate(document, 'fetchcomplete', {
     '.js-subscription-link': event => {
-      const target = event.target.closest('.js-subscription-target');
+      const target = assertNotNull(event.target.closest('.js-subscription-target'));
+
       event.detail.text().then(text => {
         target.outerHTML = text;
       });
@@ -31,40 +28,40 @@ function getNewNotifications() {
     return;
   }
 
-  makeRequest('GET').then(response => response.json()).then(({ notifications }) => {
-    updateNotificationTicker(notifications);
-    storeNotificationCount(notifications);
+  fetchJson('GET', '/notifications/unread')
+    .then(handleError).then(response => response.json())
+    .then(({ notifications }) => {
+      updateNotificationTicker(notifications);
+      storeNotificationCount(notifications);
 
-    setTimeout(getNewNotifications, NOTIFICATION_INTERVAL);
-  });
+      setTimeout(getNewNotifications, NOTIFICATION_INTERVAL);
+    });
 }
 
-function updateNotificationTicker(notificationCount) {
-  const ticker = assertNotNull($('.js-notification-ticker'));
-  const parsedNotificationCount = Number(notificationCount);
+function updateNotificationTicker(notificationCount: unknown) {
+  const ticker = assertNotNull($<HTMLSpanElement>('.js-notification-ticker'));
+  const parsedNotificationCount = Number(notificationCount as string);
 
-  ticker.dataset.notificationCount = parsedNotificationCount;
-  ticker.textContent = parsedNotificationCount;
+  ticker.dataset.notificationCount = parsedNotificationCount.toString();
+  ticker.textContent = parsedNotificationCount.toString();
 }
 
-
-function storeNotificationCount(notificationCount) {
+function storeNotificationCount(notificationCount: string) {
   // The current number of notifications are stored along with the time when the data expires
   store.setWithExpireTime('notificationCount', notificationCount, NOTIFICATION_EXPIRES);
 }
 
-
-function setupNotifications() {
+export function setupNotifications() {
   if (!window.booru.userIsSignedIn) return;
 
   // Fetch notifications from the server at a regular interval
   setTimeout(getNewNotifications, NOTIFICATION_INTERVAL);
 
   // Update the current number of notifications based on the latest page load
-  const ticker = $('.js-notification-ticker');
+  const ticker = $<HTMLSpanElement>('.js-notification-ticker');
 
   if (ticker) {
-    storeNotificationCount(ticker.dataset.notificationCount);
+    storeNotificationCount(assertNotUndefined(ticker.dataset.notificationCount));
   }
 
   // Update ticker when the stored value changes - this will occur in all open tabs
@@ -72,5 +69,3 @@ function setupNotifications() {
 
   bindSubscriptionLinks();
 }
-
-export { setupNotifications };
diff --git a/assets/js/utils/events.ts b/assets/js/utils/events.ts
index 65c2c496..e92b0109 100644
--- a/assets/js/utils/events.ts
+++ b/assets/js/utils/events.ts
@@ -1,5 +1,7 @@
 // DOM events
 
+import '../../types/ujs';
+
 export interface PhilomenaAvailableEventsMap {
   dragstart: DragEvent,
   dragover: DragEvent,
@@ -9,7 +11,8 @@ export interface PhilomenaAvailableEventsMap {
   drop: DragEvent,
   click: MouseEvent,
   submit: Event,
-  reset: Event
+  reset: Event,
+  fetchcomplete: FetchcompleteEvent
 }
 
 export interface PhilomenaEventElement {