How to Create Group Middleware

In this tutorial we will learn how to create group middleware.

How to create group middleware

To create group middleware, you can follow these steps:

Step 1 - Define the middleware function: Write a function that takes three arguments: `request`, `response`, and `next`. This function will be called for every request that passes through the middleware stack. The `next` argument is a function that you must call to pass control to the next middleware in the stack.

Step 2 - Create a router: Create a router using your framework's routing system. A router maps URLs to functions that will be called to handle requests. You can create a router by calling a method on your framework's application object or by using a separate routing library.

Step 3 - Register middleware with the router: Use the router's `use` method to register the middleware function with the router. This will add the middleware function to the middleware stack for all routes defined on the router.

Step 4 - Define routes: Define the routes that the middleware will apply to. You can define routes by calling methods on the router object, such as `get`, `post`, `put`, `delete`, etc. For each route, you can specify a callback function that will be called to handle requests.

Step 5 - Mount the router: Mount the router on your application by using the `app.use` method (or similar method) provided by your framework. This will make the middleware available to all requests that pass through the application.

Here's an example of how to create group middleware in Express.js:

const express = require('express')
const app = express()

// Define middleware function
const groupMiddleware = (req, res, next) => {
  // Do something with the request
  console.log('Group middleware executed')
  next()
}

// Create router
const router = express.Router()

// Register middleware with router
router.use(groupMiddleware)

// Define routes
router.get('/', (req, res) => {
  res.send('Hello, World!')
})

// Mount the router
app.use('/api', router)

// Start the server
app.listen(3000, () => {
  console.log('Server started on port 3000')
})

In this example, the `groupMiddleware` function is defined and registered with the router using the `use` method. The `router.get` method is used to define a route that will handle GET requests to the root URL (`/`). The router is then mounted on the application using the `app.use` method with the `/api` prefix. When a request is made to the root URL, the `groupMiddleware` function will be executed before the route callback function is called.