Writing router-level middleware functions

Router-level middleware functions are only executed inside a router. They are usually used when applying a middleware to a mount point only or to a specific path.

Getting ready

In this recipe, you will create a small logger router-level middleware function that will only log requests to paths mounted or located in the router's mounted path. Before you start, create a new package.json file with the following content:

{ 
    "dependencies": { 
        "express": "4.16.3" 
    } 
} 

Then, install the dependencies by opening a Terminal and running:

npm install

How to do it...

1. Create a new file named router-level.js
2. Initialize a new ExpressJS application and define a router:

      const express = require('express') 
      const app = express() 
      const router = express.Router() 

3. Define our logger middleware function:

      router.use((request, response, next) => { 
          console.log('URL:', request.originalUrl) 
          next() 
      }) 

4. Mount the Router...