Why Zustand State Reset Works Instantly, But React Query Cache Clearing Can Be Tricky

When working with state management and data-fetching libraries in React applications, you might encounter an interesting behavior difference during logout flows or similar global state resets. Specifically, if you use Zustand to manage user state and React Query to manage server-side data, you might notice that resetting Zustand's state works seamlessly, but clearing React Query's cache sometimes requires extra care. This blog will explain why this happens and how to handle it properly. A Common Logout Example Imagine you have a logout function like this: const onLogout = async () => { await logout(); // logout api resetUser(); // Zustand code to clear user state queryClient.clear(); // React Query code to clear cache router.push('/home'); // Navigate away };js At first glance, this looks fine. However, in practice, you might encounter inconsistent behavior with React Query's cache clearing, especially when navigating away (router.push()). You might end up doing something like this instead: const onLogout = async () => { await logout(); resetUser(); // Zustand state reset Promise.resolve().then(() => queryClient.clear()); // React Query cache clear router.push('/home'); }; Why does deferring the queryClient.clear() call with Promise.resolve() sometimes work better? And why is Zustand's resetUser() always fine? Key Difference: Zustand vs. React Query

Feb 25, 2025 - 12:53

Why Zustand State Reset Works Instantly, But React Query Cache Clearing Can Be Tricky

When working with state management and data-fetching libraries in React applications, you might encounter an interesting behavior difference during logout flows or similar global state resets. Specifically, if you use Zustand to manage user state and React Query to manage server-side data, you might notice that resetting Zustand's state works seamlessly, but clearing React Query's cache sometimes requires extra care. This blog will explain why this happens and how to handle it properly.

A Common Logout Example

Imagine you have a logout function like this:

const onLogout = async () => {
 await logout(); // logout api
 resetUser(); // Zustand code to clear user state
 queryClient.clear(); // React Query code to clear cache
 router.push('/home'); // Navigate away
};js

At first glance, this looks fine. However, in practice, you might encounter inconsistent behavior with React Query's cache clearing, especially when navigating away (router.push()).

You might end up doing something like this instead:

const onLogout = async () => {
 await logout();
 resetUser(); // Zustand state reset
 Promise.resolve().then(() => queryClient.clear()); // React Query cache clear
 router.push('/home');
};

Why does deferring the queryClient.clear() call with Promise.resolve() sometimes work better? And why is Zustand's resetUser() always fine?