diff --git a/js/src/common/Component.ts b/js/src/common/Component.ts
index a0dc5ab14..d433907df 100644
--- a/js/src/common/Component.ts
+++ b/js/src/common/Component.ts
@@ -1,4 +1,4 @@
-import Mithril from 'mithril';
+import Mithril, { ClassComponent } from 'mithril';
 
 export type ComponentProps = {
     children?: Mithril.Children;
@@ -8,8 +8,8 @@ export type ComponentProps = {
     [key: string]: any;
 };
 
-export default class Component<T extends ComponentProps = any> {
-    element: HTMLElement;
+export default class Component<T extends ComponentProps = any> implements ClassComponent {
+    element!: HTMLElement;
 
     props: T;
 
diff --git a/js/src/forum/Forum.ts b/js/src/forum/Forum.ts
index 49599992d..e9def2ffa 100644
--- a/js/src/forum/Forum.ts
+++ b/js/src/forum/Forum.ts
@@ -23,7 +23,7 @@ export default class Forum extends Application {
      */
     cache: {
         notifications?: Notification[][];
-        discussionList?: DiscussionList;
+        discussionList?: DiscussionList | null;
         [key: string]: any;
     } = {};