diff --git a/src/components/FindInPage.tsx b/src/components/FindInPage.tsx
index c5a6b591..b003074b 100644
--- a/src/components/FindInPage.tsx
+++ b/src/components/FindInPage.tsx
@@ -18,7 +18,7 @@ const InfoContainer = styled.div`
   padding: 0 12px;
 `;
 
-export default function FindInPage(): JSX.Element | undefined {
+export default function FindInPage(): JSX.Element | null {
   const [open, openSetter] = useState(false);
   const [text, textSetter] = useState('');
   const [activeMatch, activeMatchSetter] = useState(0);
@@ -50,7 +50,7 @@ export default function FindInPage(): JSX.Element | undefined {
     };
   }, [handleOpenFindInPage, updateFindInPageMatches]);
   if (!open) {
-    return;
+    return null;
   }
   return (
     <Root>
diff --git a/src/preload/common/remote.ts b/src/preload/common/remote.ts
index 6998f923..e23c94ac 100644
--- a/src/preload/common/remote.ts
+++ b/src/preload/common/remote.ts
@@ -13,7 +13,7 @@ export const remoteMethods = {
     await service.menu.buildContextMenuAndPopup(ipcSafeMenus, parameters, windowName);
     return unregister;
   },
-  closeCurrentWindow: async (): Promise<() => void> => {
+  closeCurrentWindow: async (): Promise<void> => {
     await service.window.close(windowName);
   },
   /** call NodeJS.path */