compare now with null check

src/client/src/components/todos/todoList.tsx

@@ -20,7 +20,7 @@ export const TodoList = (props: {
         return t.status == false;
       })
       .sort((a, b) => a.created - b.created)
-      .sort((a, b) => b.priority.localeCompare(a.priority));
+      .sort((a, b) => b.priority?.localeCompare(a.priority));
   }, [props.todos, props.hideDone]);
 
   return (