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/useUser.ts

@@ -0,0 +1,42 @@
+import { useState, useEffect } from "react";
+
+import type { User } from "@dndbeyond/authentication-lib-js";
+
+import { getUser } from "../helpers/userApi";
+
+export interface AppUser extends User {
+  displayName: string;
+  id: string;
+  name: string;
+  roles: Array<string>;
+  subscription: string;
+  subscriptionTier: string;
+}
+/**
+ * AppUserState has three states:
+ * - undefined: We currently don't know if the user is authenticated or not. ie loading state
+ * - null: user is not authenticated
+ * - User: user is authenticated and is a registered user
+ */
+const useUserInitialState = undefined;
+type UseUserUnauthenticated = null;
+export type AppUserState =
+  | AppUser
+  | UseUserUnauthenticated
+  | typeof useUserInitialState;
+
+const useUser = () => {
+  const [user, setUser] = useState<AppUserState>(useUserInitialState);
+
+  useEffect(() => {
+    getUser()
+      .then(setUser)
+      .catch(() => {
+        setUser(null);
+      });
+  }, []);
+
+  return user;
+};
+
+export default useUser;