Middleware in Zustand allows you to extend your store's capabilities by intercepting and enhancing actions such as state updates or retrieval. Middleware functions can be used for a variety of purposes, including logging state changes, persisting state to local storage, or even handling analytics. By wrapping your store with middleware, you can add features without modifying your state logic directly. Common use cases for middleware in Zustand include:

• Tracking state changes for debugging;
• Saving state between sessions;
• Enforcing rules or side effects whenever state is updated.

To illustrate how middleware works in Zustand, consider a scenario where you want to log every state change and also persist the state to local storage. You can achieve this by composing middleware functions when creating your store. For example, you might use a logger middleware to print changes to the console, and a persist middleware to automatically save and load state from local storage. By combining these middleware functions, your store gains both logging and persistence capabilities without any changes to your business logic.