Creating Custom Middleware

To create a custom middleware, you define a function that follows a particular pattern. This function receives the Redux store as its first parameter and returns another function. This returned function then takes next as its parameter, which represents the next middleware in the chain. Inside this function, you’ll handle your custom logic and eventually call next(action) to pass the action forward.

Step 1: Middleware Structure First, let’s define the structure of our middleware function. A middleware in Redux is a function that returns another function, which takes store as its argument. This function then returns another function that takes next as its argument, representing the next middleware in the chain.

const customMiddleware = store => next => action => {
  // Middleware logic goes here
}

Step 2: Implement Middleware Logic Inside our middleware function, we can implement the desired logic. For example, let’s create a simple logger middleware that logs each dispatched action to the console along with the current state.

const loggerMiddleware = store => next => action => {
  console.log('Dispatching action:', action);
  console.log('Current state:', store.getState());
  next(action);
}

Step 3: Apply Middleware to Redux Store to apply our custom middleware to the Redux store, we use the applyMiddleware function provided by Redux.

import { createStore, applyMiddleware } from 'redux';
import rootReducer from './reducers';
const store = createStore(rootReducer, applyMiddleware(loggerMiddleware));

In React-Redux applications, managing the flow of data is crucial for building efficient and scalable apps. Redux provides a powerful state management solution, and custom middleware adds an extra layer of flexibility to handle complex scenarios effectively.

Let’s understand custom middleware in simpler terms and see how we can create and use them.