advanced patterns When Filtering a Nested Array of Objects in React with useState Hook
I'm working on a React application (v17.0.2) where I need to filter a nested array of objects but I'm running into unexpected behavior with my state updates. I have a state variable that holds an array of user objects, each containing a list of posts. My goal is to filter out posts based on a specific criterion (e.g., `isPublished: true`). However, when I try to update the state after filtering, the result is not what I expect. Here's a simplified version of my state and filtering function: ```javascript const [users, setUsers] = useState([ { id: 1, name: 'Alice', posts: [{ id: 1, title: 'Post 1', isPublished: true }, { id: 2, title: 'Post 2', isPublished: false }] }, { id: 2, name: 'Bob', posts: [{ id: 3, title: 'Post 3', isPublished: true }] } ]); const filterPosts = () => { const filteredUsers = users.map(user => ({ ...user, posts: user.posts.filter(post => post.isPublished) })); setUsers(filteredUsers); }; ``` When I call `filterPosts`, I expect `users[0].posts` to only contain the post with `id: 1`. However, when I log the output after filtering, I see that the posts are being filtered correctly, but I'm also seeing stale state references in the React rendering. Here's what I log right after setting the new state: ```javascript console.log(filteredUsers); ``` It outputs the correct filtered structure. However, when I check the rendered output, the component shows the previous state instead of the updated one. I suspect it might be a question with how React batches state updates or a rendering scenario, but I'm not sure how to diagnose this further. Is there something wrong with how I'm updating the state, or could this be related to how React handles state updates in components? Any insights or suggestions on how to ensure my component reflects the updated state correctly would be greatly appreciated.