fixed a bug, safeguard alerts being null

src/components/Job/JobDetails.js

@@ -103,7 +103,8 @@ export const JobDetails = ({ operation, job }) => {
   );
 
   useEffect(() => {
-    setAlerts([createAlert(jobOperation, job), ...operation.alerts]);
+    const operationAlerts = operation.alerts ? operation.alerts : [];
+    setAlerts([createAlert(jobOperation, job), ...operationAlerts]);
   }, [operation, job, jobOperation]);
 
   return (