A ponyfill for React's upcoming concurrent stores API that lets you safely mutate state during non-blocking transitions today.
useSyncExternalStore is how React apps integrate with external state today — but the name says it all. It’s synchronous. Mutate a store during a useTransition and React de-opts to a blocking update, throwing away the concurrency benefits you were trying to use. The React team has announced a new concurrent store API to fix this, but it isn’t in a stable release yet.
This package is a ponyfill of that upcoming API, implemented entirely in user land. The useStore hook mirrors the planned use(store) interface: create a store with createStore(), pass it an optional reducer, and subscribe from any component. The hook handles caching, lifecycle management, and concurrent-safe updates — state changes during transitions stay non-blocking. Async stores work too: pass a Promise as the initial value and the hook integrates directly with Suspense via React’s use() hook.
The explicit goal is to generate feedback on the upcoming API while making it useful today. The migration path is designed to be mechanical: swap the import from react-use-store to react and replace useStore with use once the feature ships. No experimental React builds required — the ponyfill runs on the current stable release.