diff --git a/_packs/controllers/order_controller.js b/_packs/controllers/order_controller.js
index dea675f..5e8edb6 100644
--- a/_packs/controllers/order_controller.js
+++ b/_packs/controllers/order_controller.js
@@ -23,7 +23,7 @@ export default class extends CartBaseController {
    */
   subscribe () {
     window.addEventListener('storage', async event => {
-      if (!event.key.startsWith('cart:item:')) return
+      if (!event.key?.startsWith('cart:item:')) return
 
       const products = this.products
       const site = await this.site()