some change

src/utils/store.ts

@@ -0,0 +1,43 @@
+import { useEffect, useState } from 'react'
+
+export interface Store<T> {
+  getState: () => T
+  setState: (nextState: T | ((prevState: T) => T)) => void
+  subscribe: (listener: Listener<T>) => () => void
+}
+
+type Listener<T> = (state: T) => void
+
+export function createStore<T extends object | null>(initialState: T): Store<T> {
+  let state = initialState
+  const listeners = new Set<Listener<T>>()
+
+  const getState = () => Object.freeze(state)
+
+  function setState(nextState: T | ((prevState: T) => T)) {
+    if (typeof nextState === 'function') {
+      state = nextState(state)
+    } else {
+      state = nextState
+    }
+
+    listeners.forEach((listener) => listener(state))
+  }
+
+  function subscribe(listener: Listener<T>) {
+    listeners.add(listener)
+    return () => {
+      listeners.delete(listener)
+    }
+  }
+
+  return { getState, setState, subscribe }
+}
+
+export function useStore<T>(store: Store<T>) {
+  const [selectedState, setSelectedState] = useState(() => store.getState())
+
+  useEffect(() => store.subscribe((newState) => setSelectedState(newState)), [store])
+
+  return [selectedState, setSelectedState] as const
+}