Fixing Gatsby’s rehydration issue

Gatsby applications often encounter rehydration issues when server-side rendering (SSR) fails to match client-side data, such as user preferences stored in a browser's Local Storage. This mismatch can lead to performance problems like flickering or incorrect UI elements being displayed, such as a login button appearing instead of a logout button due to server-side rendering not having access to client-only data. To address these issues, developers can defer rendering of certain UI components until the client has fully loaded, using React Hooks to detect whether the code is running on the client or server. Utilizing the `key` attribute in React components can also force re-renders when the client state changes, helping to maintain UI consistency. The `useIsClient` hook simplifies this process by encapsulating the logic needed to determine the runtime environment, allowing developers to mitigate rehydration issues more effectively across their codebase. While SSR can significantly enhance performance by delivering fully rendered pages, careful consideration is needed to manage interactions between client and server-side data.