Handling State Updates with setInterval in React causing stale closures
I'm trying to figure out I'm wondering if anyone has experience with I'm writing unit tests and After trying multiple solutions online, I still can't figure this out. I'm working with an scenario with state updates in my React component when using `setInterval`. The component is supposed to update a count every second, but it seems to always reference the initial state value due to closures. I'm using React version 17.0.2 and functional components with hooks. Here's the relevant part of my code: ```javascript import React, { useState, useEffect } from 'react'; const Counter = () => { const [count, setCount] = useState(0); useEffect(() => { const interval = setInterval(() => { setCount(count + 1); // This always references the initial value of count }, 1000); return () => clearInterval(interval); }, []); // Empty dependency array return <div>Count: {count}</div>; }; export default Counter; ``` Even though I expect the count to increment every second, the state updates are not reflecting the current count value. Instead, it appears to be using the initial value of `count`, which is 0. I've tried adding `count` to the dependency array of `useEffect`, but that leads to multiple intervals being set up, causing the count to increase exponentially. I've also considered using a functional update with `setCount`, like this: ```javascript setCount(prevCount => prevCount + 1); ``` However, I want to understand why the closure behavior is causing this scenario and if there’s a better way to manage intervals with state updates in React components. Any insights would be greatly appreciated! For context: I'm using Javascript on Windows. Any ideas what could be causing this? The stack includes Javascript and several other technologies. Any pointers in the right direction? The stack includes Javascript and several other technologies. I'm coming from a different tech stack and learning Javascript. What's the best practice here?