diff --git a/packages/web/src/appobj/SubProcedureParamList.svelte b/packages/web/src/appobj/SubProcedureParamList.svelte
index 206321594..852775e26 100644
--- a/packages/web/src/appobj/SubProcedureParamList.svelte
+++ b/packages/web/src/appobj/SubProcedureParamList.svelte
@@ -6,10 +6,9 @@
 </script>
 
 <AppObjectList
-  list={data.parameters ||
-    [].map(parameter => ({
-      ...data,
-      ...parameter,
-    }))}
+  list={(data.parameters || []).map(parameter => ({
+    ...data,
+    ...parameter,
+  }))}
   module={parameterAppObject}
 />