diff --git a/src/matrix/storage/idb/stores/RoomMemberStore.ts b/src/matrix/storage/idb/stores/RoomMemberStore.ts
index e389bb77..00cf607f 100644
--- a/src/matrix/storage/idb/stores/RoomMemberStore.ts
+++ b/src/matrix/storage/idb/stores/RoomMemberStore.ts
@@ -52,7 +52,7 @@ export class RoomMemberStore {
 
     set(member: MemberData): void {
         // Object.assign would be more typesafe, but small objects 
-        (member as any).key = encodeKey(member.roomId, member.userId);
+        (member as MemberStorageEntry).key = encodeKey(member.roomId, member.userId);
         this._roomMembersStore.put(member as MemberStorageEntry);
     }
 
diff --git a/src/matrix/storage/idb/stores/TimelineFragmentStore.ts b/src/matrix/storage/idb/stores/TimelineFragmentStore.ts
index 54b66489..813fc3f3 100644
--- a/src/matrix/storage/idb/stores/TimelineFragmentStore.ts
+++ b/src/matrix/storage/idb/stores/TimelineFragmentStore.ts
@@ -75,7 +75,7 @@ export class TimelineFragmentStore {
     // depends if we want to do anything smart with fragment ids,
     // like give them meaning depending on range. not for now probably ...
     add(fragment: Fragment): void {
-        (fragment as any).key = encodeKey(fragment.roomId, fragment.id);
+        (fragment as FragmentEntry).key = encodeKey(fragment.roomId, fragment.id);
         this._store.add(fragment as FragmentEntry);
     }