React 18: Context API Performance Issues with Deeply Nested Components
I just started working with I'm testing a new approach and I'm experiencing significant performance degradation in my React 18 application when using the Context API to manage state across a deeply nested component tree. Specifically, I'm noticing that when I update the context value, it triggers unnecessary re-renders in components that don't actually depend on that part of the context. For instance, I have a user context that contains user details and theme preferences. The context is provided at the top level of my application: ```javascript const UserContext = React.createContext(); const UserProvider = ({ children }) => { const [user, setUser] = useState({ name: 'John Doe', theme: 'light' }); const updateTheme = (newTheme) => { setUser((prev) => ({ ...prev, theme: newTheme })); }; return ( <UserContext.Provider value={{ user, updateTheme }}> {children} </UserContext.Provider> ); }; ``` Then, in one of my deeply nested components, I'm using the context like this: ```javascript const ThemeToggle = () => { const { user, updateTheme } = useContext(UserContext); const handleToggle = () => { const newTheme = user.theme === 'light' ? 'dark' : 'light'; updateTheme(newTheme); }; return <button onClick={handleToggle}>Toggle Theme</button>; }; ``` The issue arises when the theme is toggled. The entire component tree below the `UserProvider` re-renders, even if some components are not using the `theme` value. I've tried using `React.memo` on the `ThemeToggle` component, but it hasn’t resolved the issue. I also considered splitting the context into multiple contexts for `user` and `theme`, but that feels cumbersome and might complicate my component tree further. I’m currently using React 18.0.0, and my application structure is quite large, making it challenging to track down all the components that may be inadvertently re-rendering. I would appreciate any insights on how to optimize the use of context in this scenario or alternative design patterns that could minimize unnecessary renders. Is there a best practice for managing state in a deeply nested structure without affecting performance? Am I missing something obvious? I'm coming from a different tech stack and learning Javascript. What would be the recommended way to handle this?