diff --git a/packages/modern-test-app/app/components/and-or-type-checking.ts b/packages/modern-test-app/app/components/and-or-type-checking.ts
index 793e50e..a26b5de 100644
--- a/packages/modern-test-app/app/components/and-or-type-checking.ts
+++ b/packages/modern-test-app/app/components/and-or-type-checking.ts
@@ -8,6 +8,7 @@ interface Signature {
     andArg3: true;
     andArg4: { isTruthy: true };
     orArg: object;
+    stringArg: string;
   };
 }
 
diff --git a/packages/modern-test-app/app/templates/helpers.hbs b/packages/modern-test-app/app/components/helpers.hbs
similarity index 89%
rename from packages/modern-test-app/app/templates/helpers.hbs
rename to packages/modern-test-app/app/components/helpers.hbs
index cc0df20..6bae4ce 100644
--- a/packages/modern-test-app/app/templates/helpers.hbs
+++ b/packages/modern-test-app/app/components/helpers.hbs
@@ -17,4 +17,5 @@
   @andArg3={{and true true}}
   @andArg4={{and 1 (hash isTruthy=true)}}
   @orArg={{or (hash) (array)}}
+  @stringArg={{or this.maybeString "string"}}
 />
\ No newline at end of file
diff --git a/packages/modern-test-app/app/components/helpers.ts b/packages/modern-test-app/app/components/helpers.ts
new file mode 100644
index 0000000..da4dd2b
--- /dev/null
+++ b/packages/modern-test-app/app/components/helpers.ts
@@ -0,0 +1,7 @@
+import Component from '@glimmer/component';
+
+export default class extends Component {
+  get maybeString(): string | undefined {
+    return Date.now() === 0 ? 'now has gone' : undefined;
+  }
+}