React 18: Handling Component Re-renders with Dynamic Theme Switching and useContext
I've looked through the documentation and I'm still confused about I've been struggling with this for a few days now and could really use some help... I'm currently implementing a dynamic theme switcher in my React 18 application using the Context API, but I'm facing issues with unnecessary re-renders that are affecting performance. My setup includes a `ThemeContext` that provides the current theme and a function to toggle between light and dark themes. However, when I switch themes, all components that consume this context seem to re-render, even those that don’t rely on theme-specific styles. Here's a simplified version of the context setup: ```javascript import React, { createContext, useContext, useState } from 'react'; const ThemeContext = createContext(); export const ThemeProvider = ({ children }) => { const [theme, setTheme] = useState('light'); const toggleTheme = () => { setTheme((prev) => (prev === 'light' ? 'dark' : 'light')); }; return ( <ThemeContext.Provider value={{ theme, toggleTheme }}> {children} </ThemeContext.Provider> ); }; export const useTheme = () => useContext(ThemeContext); ``` In my components, I use the `useTheme` hook to get the current theme and render styles accordingly. However, I noticed that even components that don’t use the theme value directly still re-render when the theme toggles. For instance: ```javascript const Header = () => { const { toggleTheme } = useTheme(); return <button onClick={toggleTheme}>Toggle Theme</button>; }; const Content = () => { return <div>Some static content here</div>; }; const App = () => { return ( <ThemeProvider> <Header /> <Content /> </ThemeProvider> ); }; ``` I've tried wrapping `Content` in `React.memo`, but it still re-renders. I suspect that since `useContext` triggers an update to all consumers when the context value changes, that might be causing the issue. Is there a recommended approach to optimize this situation so that only the components that actually need to react to the theme change re-render? Any insights or best practices would be greatly appreciated! For context: I'm using Javascript on macOS. How would you solve this? My development environment is Windows. Am I missing something obvious? This is happening in both development and production on CentOS. Any feedback is welcome! I'm working in a Windows 10 environment. Is there a better approach?