fix(useLocalStorage): reinitialize on key change

Author: adesurirey

src/useLocalStorage.ts

@@ -1,4 +1,4 @@
-import { Dispatch, SetStateAction, useCallback, useState } from 'react';
+import { Dispatch, SetStateAction, useCallback, useState, useRef, useLayoutEffect } from 'react';
 import { isBrowser, noop } from './misc/util';
 
 type parserOptions<T> =
@@ -30,7 +30,7 @@ const useLocalStorage = <T>(
     : JSON.parse;
 
   // eslint-disable-next-line react-hooks/rules-of-hooks
-  const [state, setState] = useState<T | undefined>(() => {
+  const initializer = useRef((key: string) => {
     try {
       const serializer = options ? (options.raw ? String : options.serializer) : JSON.stringify;
 
@@ -49,6 +49,12 @@ const useLocalStorage = <T>(
     }
   });
 
+  // eslint-disable-next-line react-hooks/rules-of-hooks
+  const [state, setState] = useState<T | undefined>(() => initializer.current(key));
+
+  // eslint-disable-next-line react-hooks/rules-of-hooks
+  useLayoutEffect(() => setState(initializer.current(key)), [key]);
+
   // eslint-disable-next-line react-hooks/rules-of-hooks
   const set: Dispatch<SetStateAction<T | undefined>> = useCallback(
     (valOrFunc) => {

tests/useLocalStorage.test.ts

@@ -80,6 +80,19 @@ describe(useLocalStorage, () => {
     expect(foo).toEqual('baz');
   });
 
+  it('reinitializes state when key changes', () => {
+    let key = 'foo';
+    const { result, rerender } = renderHook(() => useLocalStorage(key, 'bar'));
+
+    const [, setState] = result.current;
+    act(() => setState('baz'));
+    key = 'bar';
+    rerender();
+
+    const [state] = result.current;
+    expect(state).toEqual('bar');
+  });
+
   /*
   it('keeps multiple hooks accessing the same key in sync', () => {
     localStorage.setItem('foo', 'bar');