React: Handling State Updates with useEffect for Nested Components
I'm collaborating on a project where I'm stuck on something that should probably be simple. I'm working with an scenario with state updates in a React application that uses functional components and the `useEffect` hook. I have a parent component that manages a list of items and passes down the state and a function to update this state to a child component. However, I noticed that the child component doesn't re-render as expected when the state updates. Here's a simplified version of my code: ```javascript import React, { useState, useEffect } from 'react'; const ParentComponent = () => { const [items, setItems] = useState(['Item 1', 'Item 2']); const addItem = (newItem) => { setItems(prevItems => [...prevItems, newItem]); }; return ( <div> <ChildComponent items={items} addItem={addItem} /> <button onClick={() => addItem(`Item ${items.length + 1}`)}>Add Item</button> </div> ); }; const ChildComponent = ({ items }) => { useEffect(() => { console.log('ChildComponent updated', items); }, [items]); return ( <ul> {items.map((item, index) => <li key={index}>{item}</li>)} </ul> ); }; export default ParentComponent; ``` I am using React version 17.0.2. When I click the 'Add Item' button, the console logs the updated items correctly, but the child component does not render the newly added item in the list. I’ve checked the dependency array in the `useEffect`, and it seems correct. I also tried adding a simple `console.log` in the render method of `ChildComponent`, and it does fire when the button is clicked, but the list does not visually update. I suspect it might be related to how React handles re-renders for functional components, but I'm not sure where I went wrong. Has anyone else experienced this or could point me in the right direction? For context: I'm using Javascript on Windows. I'd really appreciate any guidance on this. I'm on macOS using the latest version of Javascript.