useSyncExternalStore

lib/store.ts

@@ -0,0 +1,16 @@
+export const createStore = (initialState) => {
+  let state = initialState
+  const listeners = new Set<() => void>()
+
+  return {
+    getState: () => state,
+    subscribe: (listener) => {
+      listeners.add(listener)
+      return () => {listeners.delete(listener)}
+    },
+    setState: (newState) => {
+      state = newState
+      listeners.forEach((listener) => listener())
+    },
+  }
+}