We’ve all done it. When handling a user logout in a web application, we instinctively write something like this and call it a day: const handleLogout = () => { localStorage . removeItem ( " auth_token " ); window . location . href = " /login " ; }; Enter fullscreen mode Exit fullscreen mode It feels right. The token is gone, the user is redirected, and the session should be dead. Except, it isn’t. If your application relies on modern state management (like React's useState / useContext or Vue’s Composition API ref), simple browser storage clearing commands leave framework memory completely intact. If a user logs out on a shared machine or a public terminal, and another person immediately sits down and interacts with the application framework layer before a hard browser refresh occurs, private cached reactive variables (userData, dashboardMetrics, ledgerBalances) can momentarily flash on the screen.…