diff --git a/src/hooks/useRoomState.ts b/src/hooks/useRoomState.ts
index 11ac7de49e..e778acf8a9 100644
--- a/src/hooks/useRoomState.ts
+++ b/src/hooks/useRoomState.ts
@@ -24,7 +24,10 @@ type Mapper<T> = (roomState: RoomState) => T;
 const defaultMapper: Mapper<RoomState> = (roomState: RoomState) => roomState;
 
 // Hook to simplify watching Matrix Room state
-export const useRoomState = <T extends any = RoomState>(room: Room, mapper: Mapper<T> = defaultMapper): T => {
+export const useRoomState = <T extends any = RoomState>(
+    room: Room,
+    mapper: Mapper<T> = defaultMapper as Mapper<T>,
+): T => {
     const [value, setValue] = useState<T>(room ? mapper(room.currentState) : undefined);
 
     const update = useCallback(() => {