diff --git a/.changeset/sour-snails-grow.md b/.changeset/sour-snails-grow.md
new file mode 100644
index 00000000..89ec647b
--- /dev/null
+++ b/.changeset/sour-snails-grow.md
@@ -0,0 +1,5 @@
+---
+'nxjs-runtime': patch
+---
+
+Mark `Switch` and `WebAssembly` namespaces as non-enumerable
diff --git a/apps/tests/src/wasm.ts b/apps/tests/src/wasm.ts
index 99c9e57c..6338707c 100644
--- a/apps/tests/src/wasm.ts
+++ b/apps/tests/src/wasm.ts
@@ -3,6 +3,14 @@ import * as assert from 'uvu/assert';
 
 const test = suite('WebAssembly');
 
+test('WebAssembly namespace', () => {
+	const desc = Object.getOwnPropertyDescriptor(globalThis, 'WebAssembly')!;
+	assert.equal(desc.writable, true);
+	assert.equal(desc.enumerable, false);
+	assert.equal(desc.configurable, true);
+	assert.equal(Object.prototype.toString.call(WebAssembly), '[object WebAssembly]');
+});
+
 test('simple.wasm', async () => {
 	const bin = await Switch.readFile(
 		new URL('wasm/simple.wasm', Switch.entrypoint)
diff --git a/packages/runtime/src/utils.ts b/packages/runtime/src/utils.ts
index 7268cea3..3fe110b9 100644
--- a/packages/runtime/src/utils.ts
+++ b/packages/runtime/src/utils.ts
@@ -16,16 +16,16 @@ export const def = <T extends any>(value: T, key?: string) => {
 		}
 	}
 	const proto = (value as any).prototype;
-	const isClass = typeof proto === 'object';
+	const isClass = key[0] === key[0].toUpperCase();
 	if (isClass) {
-		Object.defineProperty(proto, Symbol.toStringTag, {
+		Object.defineProperty(proto || value, Symbol.toStringTag, {
 			value: key,
 		});
 	}
 	Object.defineProperty(globalThis, key, {
 		value,
 		writable: true,
-		enumerable: false,
+		enumerable: !isClass,
 		configurable: true,
 	});
 	return value;