Use default error title and error code

Author: aarmam

example/src/main/resources/static/js/errors.js

@@ -32,10 +32,9 @@ export function hideErrorMessage() {
     alertUi.alert.style.display = "none";
 }
 
-export function showErrorMessage(error) {
-    const message = "Authentication failed";
+export function showErrorMessage(error, message = "Authentication failed") {
     const details =
-        `[Code]\n${error.code}` +
+        `[Code]\n${error.code ?? "UNKNOWN_ERROR"}` +
         `\n\n[Message]\n${error.message}` +
         (error.response ? `\n\n[response]\n${JSON.stringify(error.response, null, " ")}` : "");
 
@@ -56,4 +55,4 @@ export async function checkHttpError(response) {
         error.code = response.status;
         throw error;
     }
-}
+}