diff --git a/tools/test-js-with-node b/tools/test-js-with-node
index 24e288dd06..b2df22c002 100755
--- a/tools/test-js-with-node
+++ b/tools/test-js-with-node
@@ -290,7 +290,7 @@ EXEMPT_FILES = make_set(
         "web/src/zcommand.ts",
         "web/src/zform.js",
         "web/src/zulip.js",
-        "web/src/zulip_test.js",
+        "web/src/zulip_test.ts",
         "web/tests/lib/mdiff.js",
         "web/tests/lib/real_jquery.js",
         "web/tests/lib/zjquery_element.js",
diff --git a/web/e2e-tests/compose.test.ts b/web/e2e-tests/compose.test.ts
index 3c3e6c3381..81d5ae3861 100644
--- a/web/e2e-tests/compose.test.ts
+++ b/web/e2e-tests/compose.test.ts
@@ -78,10 +78,9 @@ async function test_reply_by_click_prepopulates_private_message_recipient(
     assert.ok(private_message !== null);
     await private_message.click();
     await page.waitForSelector("#private_message_recipient", {visible: true});
-    await common.pm_recipient.expect(
-        page,
-        await common.get_internal_email_from_name(page, "cordelia"),
-    );
+    const email = await common.get_internal_email_from_name(page, "cordelia");
+    assert(email !== undefined);
+    await common.pm_recipient.expect(page, email);
     await close_compose_box(page);
 }
 
diff --git a/web/e2e-tests/lib/common.ts b/web/e2e-tests/lib/common.ts
index bf0fc59178..a3a04bfc72 100644
--- a/web/e2e-tests/lib/common.ts
+++ b/web/e2e-tests/lib/common.ts
@@ -26,7 +26,7 @@ export const is_firefox = process.env.PUPPETEER_PRODUCT === "firefox";
 let realm_url = "http://zulip.zulipdev.com:9981/";
 const gps = new StackTraceGPS({ajax: async (url) => (await fetch(url)).text()});
 
-let last_current_msg_list_id: number | null = null;
+let last_current_msg_list_id: number | undefined;
 
 export const pm_recipient = {
     async set(page: Page, recipient: string): Promise<void> {
@@ -231,27 +231,30 @@ export function has_class_x(class_name: string): string {
     return `contains(concat(" ", @class, " "), " ${class_name} ")`;
 }
 
-export async function get_stream_id(page: Page, stream_name: string): Promise<number> {
+export async function get_stream_id(page: Page, stream_name: string): Promise<number | undefined> {
     return await page.evaluate(
         (stream_name: string) => zulip_test.get_stream_id(stream_name),
         stream_name,
     );
 }
 
-export async function get_user_id_from_name(page: Page, name: string): Promise<number> {
+export async function get_user_id_from_name(page: Page, name: string): Promise<number | undefined> {
     if (fullname[name] !== undefined) {
         name = fullname[name];
     }
     return await page.evaluate((name: string) => zulip_test.get_user_id_from_name(name), name);
 }
 
-export async function get_internal_email_from_name(page: Page, name: string): Promise<string> {
+export async function get_internal_email_from_name(
+    page: Page,
+    name: string,
+): Promise<string | undefined> {
     if (fullname[name] !== undefined) {
         name = fullname[name];
     }
     return await page.evaluate((fullname: string) => {
         const user_id = zulip_test.get_user_id_from_name(fullname);
-        return zulip_test.get_person_by_user_id(user_id).email;
+        return user_id === undefined ? undefined : zulip_test.get_person_by_user_id(user_id).email;
     }, name);
 }
 
@@ -359,7 +362,7 @@ export async function wait_for_fully_processed_message(page: Page, content: stri
                     - does it look to have been
                       re-rendered based on server info?
             */
-            const last_msg = zulip_test.current_msg_list.last();
+            const last_msg = zulip_test.current_msg_list?.last();
             if (last_msg === undefined) {
                 return false;
             }
@@ -463,7 +466,9 @@ export async function send_message(
     }
 
     // Close the compose box after sending the message.
-    await page.evaluate(() => zulip_test.cancel_compose());
+    await page.evaluate(() => {
+        zulip_test.cancel_compose();
+    });
     // Make sure the compose box is closed.
     await page.waitForSelector("#compose-textarea", {hidden: true});
 }
@@ -731,12 +736,18 @@ export async function get_current_msg_list_id(
         // NOTE: This only checks if the current message list id changed from the last call to this function,
         // so, make sure to have a call to this function before changing to the narrow that you want to check.
         await page.waitForFunction(
-            (last_current_msg_list_id) =>
-                zulip_test.current_msg_list.id !== last_current_msg_list_id,
+            (last_current_msg_list_id) => {
+                const current_msg_list = zulip_test.current_msg_list;
+                return (
+                    current_msg_list !== undefined &&
+                    current_msg_list.id !== last_current_msg_list_id
+                );
+            },
             {},
             last_current_msg_list_id,
         );
     }
-    last_current_msg_list_id = await page.evaluate(() => zulip_test.current_msg_list.id);
-    return last_current_msg_list_id!;
+    last_current_msg_list_id = await page.evaluate(() => zulip_test.current_msg_list?.id);
+    assert(last_current_msg_list_id !== undefined);
+    return last_current_msg_list_id;
 }
diff --git a/web/e2e-tests/mention.test.ts b/web/e2e-tests/mention.test.ts
index 0fa6ff33c9..4f680d43dc 100644
--- a/web/e2e-tests/mention.test.ts
+++ b/web/e2e-tests/mention.test.ts
@@ -20,7 +20,7 @@ async function test_mention(page: Page): Promise<void> {
 
     console.log("Checking for all everyone warning");
     const stream_size = await page.evaluate(() =>
-        zulip_test.get_subscriber_count(zulip_test.get_sub("Verona").stream_id),
+        zulip_test.get_subscriber_count(zulip_test.get_sub("Verona")!.stream_id),
     );
     const threshold = await page.evaluate(() => {
         zulip_test.set_wildcard_mention_threshold(5);
diff --git a/web/e2e-tests/message-basics.test.ts b/web/e2e-tests/message-basics.test.ts
index 674a92c01f..8e19a06503 100644
--- a/web/e2e-tests/message-basics.test.ts
+++ b/web/e2e-tests/message-basics.test.ts
@@ -6,6 +6,7 @@ import * as common from "./lib/common";
 
 async function get_stream_li(page: Page, stream_name: string): Promise<string> {
     const stream_id = await common.get_stream_id(page, stream_name);
+    assert(stream_id !== undefined);
     return `#stream_filters [data-stream-id="${CSS.escape(stream_id.toString())}"]`;
 }
 
diff --git a/web/e2e-tests/navigation.test.ts b/web/e2e-tests/navigation.test.ts
index ae5208d36e..e4300198f6 100644
--- a/web/e2e-tests/navigation.test.ts
+++ b/web/e2e-tests/navigation.test.ts
@@ -64,12 +64,15 @@ async function navigate_to_private_messages(page: Page): Promise<void> {
 }
 
 async function test_reload_hash(page: Page): Promise<void> {
-    const initial_page_load_time = await page.evaluate((): number => zulip_test.page_load_time);
+    const initial_page_load_time = await page.evaluate(() => zulip_test.page_load_time);
+    assert(initial_page_load_time !== undefined);
     console.log(`initial load time: ${initial_page_load_time}`);
 
     const initial_hash = await page.evaluate(() => window.location.hash);
 
-    await page.evaluate(() => zulip_test.initiate_reload({immediate: true}));
+    await page.evaluate(() => {
+        zulip_test.initiate_reload({immediate: true});
+    });
     await page.waitForNavigation();
     const message_list_id = await common.get_current_msg_list_id(page, true);
     await page.waitForSelector(`.message-list[data-message-list-id='${message_list_id}']`, {
@@ -77,6 +80,7 @@ async function test_reload_hash(page: Page): Promise<void> {
     });
 
     const page_load_time = await page.evaluate(() => zulip_test.page_load_time);
+    assert(page_load_time !== undefined);
     assert.ok(page_load_time > initial_page_load_time, "Page not reloaded.");
 
     const hash = await page.evaluate(() => window.location.hash);
@@ -88,7 +92,7 @@ async function navigation_tests(page: Page): Promise<void> {
 
     await navigate_to_settings(page);
 
-    const verona_id = await page.evaluate((): number => zulip_test.get_stream_id("Verona"));
+    const verona_id = await page.evaluate(() => zulip_test.get_stream_id("Verona"));
     const verona_narrow = `narrow/stream/${verona_id}-Verona`;
 
     await navigate_using_left_sidebar(page, verona_narrow);
diff --git a/web/e2e-tests/stream_create.test.ts b/web/e2e-tests/stream_create.test.ts
index d8f835d489..c7624eff90 100644
--- a/web/e2e-tests/stream_create.test.ts
+++ b/web/e2e-tests/stream_create.test.ts
@@ -22,7 +22,9 @@ async function await_user_hidden(page: Page, name: string): Promise<void> {
 
 async function add_user_to_stream(page: Page, name: string): Promise<void> {
     const user_id = await common.get_user_id_from_name(page, name);
-    await page.evaluate((user_id) => zulip_test.add_user_id_to_new_stream(user_id), user_id);
+    await page.evaluate((user_id) => {
+        zulip_test.add_user_id_to_new_stream(user_id);
+    }, user_id);
     await await_user_visible(page, name);
 }
 
diff --git a/web/e2e-tests/user-deactivation.test.ts b/web/e2e-tests/user-deactivation.test.ts
index 9ef4fabf0d..968940765a 100644
--- a/web/e2e-tests/user-deactivation.test.ts
+++ b/web/e2e-tests/user-deactivation.test.ts
@@ -19,6 +19,7 @@ async function navigate_to_user_list(page: Page): Promise<void> {
 
 async function user_row(page: Page, name: string): Promise<string> {
     const user_id = await common.get_user_id_from_name(page, name);
+    assert(user_id !== undefined);
     return `.user_row[data-user-id="${CSS.escape(user_id.toString())}"]`;
 }
 
diff --git a/web/src/global.ts b/web/src/global.ts
index 4ac48be0a3..796d4bf5f1 100644
--- a/web/src/global.ts
+++ b/web/src/global.ts
@@ -1,11 +1,6 @@
-// These declarations tell the TypeScript compiler about the existence
-// of the global variables for our untyped JavaScript modules.  Please
-// remove each declaration when the corresponding module is migrated
-// to TS.
-
 /// <reference types="spectrum" />
 
-export {};
+import type * as zulip_test_module from "./zulip_test";
 
 type JQueryCaretRange = {
     start: number;
@@ -23,7 +18,7 @@ type JQueryIdleOptions = Partial<{
 }>;
 
 declare global {
-    let zulip_test: any; // eslint-disable-line @typescript-eslint/no-explicit-any
+    const zulip_test: typeof zulip_test_module;
 
     // eslint-disable-next-line @typescript-eslint/no-namespace
     namespace JQueryValidation {
diff --git a/web/src/message_lists.ts b/web/src/message_lists.ts
index 95830a0747..5b9400f2e0 100644
--- a/web/src/message_lists.ts
+++ b/web/src/message_lists.ts
@@ -48,6 +48,7 @@ export type MessageList = {
         messages: Message[],
         append_opts: {messages_are_new: boolean},
     ) => RenderInfo | undefined;
+    last: () => Message | undefined;
 };
 
 export let current: MessageList | undefined;
diff --git a/web/src/message_store.ts b/web/src/message_store.ts
index 62d54433c6..3f0e092c51 100644
--- a/web/src/message_store.ts
+++ b/web/src/message_store.ts
@@ -115,6 +115,7 @@ export type Message = (
     clean_reactions: Map<string, MessageCleanReaction>;
 
     locally_echoed?: boolean;
+    raw_content?: string;
 
     // Added in `message_helper.process_new_message`.
     sent_by_me: boolean;
diff --git a/web/src/zulip_test.js b/web/src/zulip_test.ts
similarity index 88%
rename from web/src/zulip_test.js
rename to web/src/zulip_test.ts
index e3ea7e75e3..d642a7128c 100644
--- a/web/src/zulip_test.js
+++ b/web/src/zulip_test.ts
@@ -10,7 +10,9 @@ export {get_by_user_id as get_person_by_user_id, get_user_id_from_name} from "./
 export {last_visible as last_visible_row, id as row_id} from "./rows";
 export {cancel as cancel_compose} from "./compose_actions";
 export {page_params, page_params_parse_time} from "./base_page_params";
+// @ts-expect-error We haven't converted reload.js yet
 export {initiate as initiate_reload} from "./reload";
 export {page_load_time} from "./setup";
 export {current_user, realm} from "./state_data";
+// @ts-expect-error We haven't converted stream_create_subscribers.js yet
 export {add_user_id_to_new_stream} from "./stream_create_subscribers";