diff --git a/packages/oidc-client/src/initWorker.ts b/packages/oidc-client/src/initWorker.ts
index cbefd282d..ff6e89b48 100644
--- a/packages/oidc-client/src/initWorker.ts
+++ b/packages/oidc-client/src/initWorker.ts
@@ -63,7 +63,7 @@ const sendMessageAsync =
     return new Promise(function (resolve, reject) {
       const messageChannel = new MessageChannel();
       messageChannel.port1.onmessage = function (event) {
-        if (event.data && event.data.error) {
+        if (event?.data.error) {
           reject(event.data.error);
         } else {
           resolve(event.data);