diff --git a/demos/test-app/src/index.ts b/demos/test-app/src/index.ts
index a533648c82..04cfa392b9 100644
--- a/demos/test-app/src/index.ts
+++ b/demos/test-app/src/index.ts
@@ -40,7 +40,9 @@ const customMessageBtn = document.getElementById(
 ) as HTMLButtonElement;
 const messagesEl = document.getElementById("messages") as HTMLElement;
 const hostUrlEl = document.getElementById("hostUrl") as HTMLInputElement;
-const whoAmIResponseEl = document.getElementById("whoamiResponse");
+const whoAmIResponseEl = document.getElementById(
+  "whoamiResponse"
+) as HTMLDivElement;
 const alternativeOriginsEl = document.getElementById(
   "alternativeOrigins"
 ) as HTMLDivElement;
@@ -300,7 +302,7 @@ const init = async () => {
 
 init();
 
-whoamiBtn!.addEventListener("click", async () => {
+whoamiBtn.addEventListener("click", async () => {
   const identity = await authClient.getIdentity();
   const canisterId = Principal.fromText(readCanisterId());
   const actor = Actor.createActor(idlFactory, {
@@ -311,13 +313,13 @@ whoamiBtn!.addEventListener("click", async () => {
     canisterId,
   });
 
-  whoAmIResponseEl!.innerText = "Loading...";
+  whoAmIResponseEl.innerText = "Loading...";
 
   // Similar to the sample project on dfx new:
   actor
     .whoami()
     .then((principal: any) => {
-      whoAmIResponseEl!.innerText = principal.toText();
+      whoAmIResponseEl.innerText = principal.toText();
     })
     .catch((err) => {
       console.error("Failed to fetch whoami", err);