Add non-disruptive cleanup to useDocumentTitle hook

src/hooks/useDocumentTitle.ts

@@ -1,11 +1,12 @@
 import {useFocusEffect} from '@react-navigation/native';
 import {useCallback} from 'react';
-import {setPageTitle} from '@libs/UnreadIndicatorUpdater/updateUnread';
+import {clearPageTitle, setPageTitle} from '@libs/UnreadIndicatorUpdater/updateUnread';
 
 function useDocumentTitle(title: string) {
     useFocusEffect(
         useCallback(() => {
             setPageTitle(title);
+            return () => clearPageTitle();
         }, [title]),
     );
 }

src/libs/UnreadIndicatorUpdater/updateUnread/index.android.ts

@@ -7,5 +7,7 @@ const updateUnread: UpdateUnread = () => {};
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 function setPageTitle(_title: string) {}
 
+function clearPageTitle() {}
+
 export default updateUnread;
-export {setPageTitle};
+export {clearPageTitle, setPageTitle};

src/libs/UnreadIndicatorUpdater/updateUnread/index.ios.ts

@@ -13,5 +13,7 @@ const updateUnread: UpdateUnread = (totalCount) => {
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 function setPageTitle(_title: string) {}
 
+function clearPageTitle() {}
+
 export default updateUnread;
-export {setPageTitle};
+export {clearPageTitle, setPageTitle};

src/libs/UnreadIndicatorUpdater/updateUnread/index.ts

@@ -52,5 +52,14 @@ window.addEventListener('popstate', () => {
     updateUnread(unreadTotalCount);
 });
 
+/**
+ * Clear the page title without triggering a document title update.
+ * Used as cleanup in useDocumentTitle to avoid the "New Expensify" flash
+ * that occurs when setPageTitle('') queues an async updateDocumentTitle().
+ */
+function clearPageTitle() {
+    currentPageTitle = '';
+}
+
 export default updateUnread;
-export {setPageTitle};
+export {clearPageTitle, setPageTitle};