Grabbed dndbeyond's source code

```
~/go/bin/sourcemapper -output ddb -jsurl https://media.dndbeyond.com/character-app/static/js/main.90aa78c5.js
```

ddb_main/hooks/useUserId.ts

@@ -0,0 +1,17 @@
+import { useState, useEffect } from "react";
+
+import { getUserId } from "../helpers/userApi";
+
+const useUserId = (defaultUserId?: number) => {
+  const [userId, setUserId] = useState<number | undefined>(defaultUserId);
+
+  useEffect(() => {
+    getUserId().then((user) => {
+      setUserId(user as unknown as number);
+    });
+  }, []);
+
+  return userId;
+};
+
+export default useUserId;