Unexpected behavior with React's useEffect when manipulating localStorage and async calls
I've searched everywhere and can't find a clear answer. I'm writing unit tests and I've been struggling with this for a few days now and could really use some help. I’m experiencing an unexpected behavior with the `useEffect` hook in my React application. I’m trying to synchronize some state with `localStorage`, and I want to make sure it updates correctly when the component mounts. However, I noticed that my `useEffect` is not firing as expected when I change the state after retrieving the value from `localStorage`. Here’s what my code looks like: ```javascript import React, { useEffect, useState } from 'react'; const App = () => { const [data, setData] = useState(''); useEffect(() => { const storedData = localStorage.getItem('myData'); if (storedData) { setData(storedData); } }, []); const handleChange = (event) => { const newValue = event.target.value; setData(newValue); localStorage.setItem('myData', newValue); }; return ( <div> <input type="text" value={data} onChange={handleChange} /> <p>Stored Value: {data}</p> </div> ); }; export default App; ``` The issue I am facing is when I first load the app, the input box is empty even though `localStorage` has a value saved. My expectation is that `setData` should set the state from `localStorage`, but it seems the input is not reflecting that value initially. I’ve checked that `localStorage` does contain the correct data, and I even logged the `storedData` value inside the effect. I also tried adding a dependency array to the `useEffect`, but that didn’t help either. The strange part is that if I manually refresh the page, it works fine. I’m using React 18 and have confirmed that this issue persists in both development and production builds. Can anyone provide insight into why this might be happening? Am I missing something about how `useEffect` works here? Is there a better way to handle synchronization with `localStorage`? I'm working with Javascript in a Docker container on CentOS. What's the correct way to implement this? This issue appeared after updating to Javascript LTS.