👀 Views: 98 💬 Answers: 1 📅 Created: 2025-06-13

react usestate usereducer performance javascript

I'm refactoring my project and I'm testing a new approach and I've looked through the documentation and I'm still confused about I'm currently using `useReducer` to manage state in my React application, and I'm working with issues with updating a deeply nested object without triggering unnecessary re-renders of my child components. I'm using React 18 and have the following state structure: ```javascript const initialState = { user: { details: { name: '', age: 0, }, preferences: { theme: 'light', notifications: true, }, }, }; function reducer(state, action) { switch (action.type) { case 'UPDATE_USER_DETAILS': return { ...state, user: { ...state.user, details: { ...state.user.details, ...action.payload, }, }, }; case 'TOGGLE_NOTIFICATIONS': return { ...state, user: { ...state.user, preferences: { ...state.user.preferences, notifications: !state.user.preferences.notifications, }, }, }; default: return state; } } ``` I'm dispatching an action like this to update the `name`: ```javascript dispatch({ type: 'UPDATE_USER_DETAILS', payload: { name: 'John Doe' } }); ``` The question I'm working with is that every time I update the `user.details`, it seems to be re-rendering all of my child components that rely on `user.preferences`, even though those values haven't changed. I’m using memoization with `React.memo` for these components, but it doesn’t seem to be effective. I’ve also tried adding a custom comparison function but that didn’t help either. Is there a better way to structure my state or handle updates to ensure that only the relevant components re-render? Any best practices for optimizing this pattern with nested objects would be greatly appreciated. I'm seeing warnings about excessive re-renders in the console, which is concerning, especially in a larger application where performance is critical. I'd love to hear your thoughts on this. My development environment is Debian. This issue appeared after updating to Javascript 3.9. This is my first time working with Javascript latest.