Why do we need middleware in Redux for async request calls?

Image taken from designing for scale

In Redux, the store is the single source of truth that holds the state of your application. When an action is dispatched to the store, it passes through a series of middleware before reaching the reducer.

Middleware functions are functions that run before or after an action is dispatched to the reducer. They can perform additional actions like logging, handling asynchronous requests, and modifying the action before it reaches the reducer.

For example, let’s say you have an application that needs to fetch data from an API. You would dispatch an action to request the data, but since API requests are asynchronous, you wouldn’t want the reducer to immediately update the state with incomplete data.

This is where middleware comes in. You can create middleware that intercepts the action, sends the API request, and then dispatches a new action with the updated data when the request is complete. This way, your reducer only updates the state when all of the data is available.

Another example is error handling. If an error occurs during an action, middleware can catch the error and dispatch a new action to handle it. This can help you avoid writing redundant error handling code in multiple places.

So, the purpose of middleware in Redux is to provide a flexible way to add additional functionality to the store’s dispatch process. It allows you to keep your reducer focused on updating the state, while handling other tasks like asynchronous requests and error handling in a centralized location.

Middleware is a powerful tool in Redux because it allows you to add reusable, composable logic to your application’s dispatch process. You can use middleware to handle common tasks like authentication, caching, or logging, and you can also write custom middleware functions to handle application-specific tasks.

Overall, middleware is an important part of the Redux ecosystem, as it allows you to customize and extend the behavior of your application’s dispatch process in a flexible and modular way.