diff --git a/tools/test-js-with-node b/tools/test-js-with-node
index 38458980f1..93ef7c6e5e 100755
--- a/tools/test-js-with-node
+++ b/tools/test-js-with-node
@@ -139,7 +139,7 @@ EXEMPT_FILES = make_set(
         "web/src/message_list_tooltips.js",
         "web/src/message_list_view.js",
         "web/src/message_lists.ts",
-        "web/src/message_live_update.js",
+        "web/src/message_live_update.ts",
         "web/src/message_notifications.js",
         "web/src/message_scroll.js",
         "web/src/message_scroll_state.ts",
diff --git a/web/src/message_live_update.js b/web/src/message_live_update.ts
similarity index 79%
rename from web/src/message_live_update.js
rename to web/src/message_live_update.ts
index d59dfaf511..578fbba965 100644
--- a/web/src/message_live_update.js
+++ b/web/src/message_live_update.ts
@@ -2,13 +2,13 @@ import * as message_lists from "./message_lists";
 import * as message_store from "./message_store";
 import * as people from "./people";
 
-export function rerender_messages_view() {
+export function rerender_messages_view(): void {
     for (const list of message_lists.all_rendered_message_lists()) {
         list.rerender_view();
     }
 }
 
-export function rerender_messages_view_by_message_ids(message_ids) {
+export function rerender_messages_view_by_message_ids(message_ids: number[]): void {
     const messages_to_render = [];
     for (const id of message_ids) {
         const message = message_store.get(id);
@@ -21,7 +21,7 @@ export function rerender_messages_view_by_message_ids(message_ids) {
     }
 }
 
-function rerender_messages_view_for_user(user_id) {
+function rerender_messages_view_for_user(user_id: number): void {
     for (const list of message_lists.all_rendered_message_lists()) {
         const messages = list.data.get_messages_sent_by_user(user_id);
         if (messages.length === 0) {
@@ -31,7 +31,10 @@ function rerender_messages_view_for_user(user_id) {
     }
 }
 
-export function update_message_in_all_views(message_id, callback) {
+export function update_message_in_all_views(
+    message_id: number,
+    callback: ($row: JQuery) => void,
+): void {
     for (const msg_list of message_lists.all_rendered_message_lists()) {
         const $row = msg_list.get_row(message_id);
         if ($row === undefined) {
@@ -43,7 +46,7 @@ export function update_message_in_all_views(message_id, callback) {
     }
 }
 
-export function update_starred_view(message_id, new_value) {
+export function update_starred_view(message_id: number, new_value: boolean): void {
     const starred = new_value;
 
     // Avoid a full re-render, but update the star in each message
@@ -65,24 +68,24 @@ export function update_starred_view(message_id, new_value) {
     });
 }
 
-export function update_stream_name(stream_id, new_name) {
+export function update_stream_name(stream_id: number, new_name: string): void {
     message_store.update_stream_name(stream_id, new_name);
     rerender_messages_view();
 }
 
-export function update_user_full_name(user_id, full_name) {
+export function update_user_full_name(user_id: number, full_name: string): void {
     message_store.update_sender_full_name(user_id, full_name);
     rerender_messages_view_for_user(user_id);
 }
 
-export function update_avatar(user_id, avatar_url) {
+export function update_avatar(user_id: number, avatar_url: string): void {
     let url = avatar_url;
     url = people.format_small_avatar_url(url);
     message_store.update_small_avatar_url(user_id, url);
     rerender_messages_view_for_user(user_id);
 }
 
-export function update_user_status_emoji(user_id, status_emoji_info) {
+export function update_user_status_emoji(user_id: number, status_emoji_info: string): void {
     message_store.update_status_emoji_info(user_id, status_emoji_info);
     rerender_messages_view_for_user(user_id);
 }