diff --git a/tools/test-js-with-node b/tools/test-js-with-node
index ecab212be9..6943ce06c2 100755
--- a/tools/test-js-with-node
+++ b/tools/test-js-with-node
@@ -284,7 +284,7 @@ EXEMPT_FILES = make_set(
         "web/src/user_status_ui.ts",
         "web/src/user_topic_popover.js",
         "web/src/user_topics.ts",
-        "web/src/user_topics_ui.js",
+        "web/src/user_topics_ui.ts",
         "web/src/views_util.ts",
         "web/src/zcommand.ts",
         "web/src/zform.js",
diff --git a/web/src/message_lists.ts b/web/src/message_lists.ts
index 13cbc5120c..cf411f3c60 100644
--- a/web/src/message_lists.ts
+++ b/web/src/message_lists.ts
@@ -45,6 +45,7 @@ export type MessageList = {
     can_mark_messages_read: () => boolean;
     can_mark_messages_read_without_setting: () => boolean;
     rerender_view: () => void;
+    update_muting_and_rerender: () => void;
     prevent_reading: () => void;
     resume_reading: () => void;
     data: MessageListData;
diff --git a/web/src/user_topics.ts b/web/src/user_topics.ts
index 5a781ed3ac..1a7840bfb4 100644
--- a/web/src/user_topics.ts
+++ b/web/src/user_topics.ts
@@ -15,7 +15,7 @@ import * as timerender from "./timerender";
 import * as ui_report from "./ui_report";
 import {get_time_from_date_muted} from "./util";
 
-type ServerUserTopic = z.infer<typeof user_topic_schema>;
+export type ServerUserTopic = z.infer<typeof user_topic_schema>;
 
 export type UserTopic = {
     stream_id: number;
diff --git a/web/src/user_topics_ui.js b/web/src/user_topics_ui.ts
similarity index 89%
rename from web/src/user_topics_ui.js
rename to web/src/user_topics_ui.ts
index 40415d0e20..58150b6b4a 100644
--- a/web/src/user_topics_ui.js
+++ b/web/src/user_topics_ui.ts
@@ -1,6 +1,7 @@
 import $ from "jquery";
 
 import * as message_lists from "./message_lists";
+import type {Message} from "./message_store";
 import * as overlays from "./overlays";
 import * as popover_menus from "./popover_menus";
 import * as recent_view_ui from "./recent_view_ui";
@@ -9,8 +10,9 @@ import * as stream_list from "./stream_list";
 import * as sub_store from "./sub_store";
 import * as unread_ui from "./unread_ui";
 import * as user_topics from "./user_topics";
+import type {ServerUserTopic} from "./user_topics";
 
-export function handle_topic_updates(user_topic_event) {
+export function handle_topic_updates(user_topic_event: ServerUserTopic): void {
     // Update the UI after changes in topic visibility policies.
     user_topics.set_user_topic(user_topic_event);
     popover_menus.get_topic_menu_popover()?.hide();
@@ -56,7 +58,11 @@ export function handle_topic_updates(user_topic_event) {
     }, 0);
 }
 
-export function toggle_topic_visibility_policy(message) {
+export function toggle_topic_visibility_policy(message: Message): void {
+    if (message.type !== "stream") {
+        return;
+    }
+
     const stream_id = message.stream_id;
     const topic = message.topic;
 
@@ -69,8 +75,8 @@ export function toggle_topic_visibility_policy(message) {
             topic,
             user_topics.all_visibility_policies.INHERIT,
         );
-    } else if (message.type === "stream") {
-        if (sub_store.get(stream_id).is_muted) {
+    } else {
+        if (sub_store.get(stream_id)?.is_muted) {
             user_topics.set_user_topic_visibility_policy(
                 stream_id,
                 topic,