diff --git a/src/material/BottomSheet.tsx b/src/material/BottomSheet.tsx
index 99bfbd0..5b463a0 100644
--- a/src/material/BottomSheet.tsx
+++ b/src/material/BottomSheet.tsx
@@ -51,7 +51,7 @@ function animateSlideInFromBottom(element: HTMLElement, reverse?: boolean) {
 }
 
 const BottomSheet: ParentComponent<BottomSheetProps> = (props) => {
-  let element: HTMLDialogElement;
+  let element!: HTMLDialogElement;
   let animation: Animation | undefined;
   const child = children(() => props.children);
 
diff --git a/src/material/Menu.tsx b/src/material/Menu.tsx
index 931b756..3bc2ab0 100644
--- a/src/material/Menu.tsx
+++ b/src/material/Menu.tsx
@@ -108,7 +108,7 @@ function animateGrowFromTopLeft(
  * - Use {@link MenuItem} from SUID as children.
  */
 const Menu: Component<MenuProps> = (oprops) => {
-  let root: HTMLDialogElement;
+  let root!: HTMLDialogElement;
   const windowSize = useWindowSize();
   const [props, rest] = splitProps(oprops, [
     "open",
diff --git a/src/timelines/MediaViewer.tsx b/src/timelines/MediaViewer.tsx
index ba92772..af3ef7b 100644
--- a/src/timelines/MediaViewer.tsx
+++ b/src/timelines/MediaViewer.tsx
@@ -38,7 +38,7 @@ function clamp(input: number, min: number, max: number) {
 }
 
 const MediaViewer: ParentComponent<MediaViewerProps> = (props) => {
-  let rootRef: HTMLDialogElement;
+  let rootRef!: HTMLDialogElement;
 
   type State = {
     ref?: HTMLElement;
diff --git a/src/timelines/PullDownToRefresh.tsx b/src/timelines/PullDownToRefresh.tsx
index 4f829ee..6393050 100644
--- a/src/timelines/PullDownToRefresh.tsx
+++ b/src/timelines/PullDownToRefresh.tsx
@@ -17,7 +17,7 @@ const PullDownToRefresh: Component<{
   linkedElement?: HTMLElement;
   onRefresh?: () => void;
 }> = (props) => {
-  let rootElement: HTMLDivElement;
+  let rootElement!: HTMLDivElement;
   const [pullDown, setPullDown] = createSignal(0);
 
   const stopPos = () => 160;
diff --git a/src/timelines/TootLangPicker.tsx b/src/timelines/TootLangPicker.tsx
index e86f69e..7ed1055 100644
--- a/src/timelines/TootLangPicker.tsx
+++ b/src/timelines/TootLangPicker.tsx
@@ -23,7 +23,7 @@ type ChooseTootLangProps = {
 };
 
 const ChooseTootLang: Component<ChooseTootLangProps> = (props) => {
-  let listRef: HTMLUListElement;
+  let listRef!: HTMLUListElement;
   const [t] = createTranslator(
     (code) =>
       import(`./i18n/${code}.json`) as Promise<{
diff --git a/src/timelines/toots/PreviewCard.tsx b/src/timelines/toots/PreviewCard.tsx
index 5e6780e..c4b4036 100644
--- a/src/timelines/toots/PreviewCard.tsx
+++ b/src/timelines/toots/PreviewCard.tsx
@@ -17,7 +17,7 @@ export function PreviewCard(props: {
   src: mastodon.v1.PreviewCard;
   alwaysCompact?: boolean;
 }) {
-  let root: HTMLAnchorElement;
+  let root!: HTMLAnchorElement;
 
   createEffect(() => {
     if (props.alwaysCompact) {
diff --git a/src/timelines/toots/TootPoll.tsx b/src/timelines/toots/TootPoll.tsx
index a2b9dc6..5c08c21 100644
--- a/src/timelines/toots/TootPoll.tsx
+++ b/src/timelines/toots/TootPoll.tsx
@@ -33,7 +33,7 @@ type TootPollProps = {
 };
 
 const TootPoll: Component<TootPollProps> = (props) => {
-  let list: HTMLUListElement;
+  let list!: HTMLUListElement;
   const { vote } = useTootEnv();
 
   const now = useTimeSource();