Creating and Importing Routers in Node.js and Express Guide

Q: How do I create a router in Express?

You can create a router using express.Router() , define routes inside it, and export the router module. Then, import and use it in your main app.js file.

Q: Can I have nested routers in Express?

Yes, routers can be nested using router.use() . This allows you to organize routes into a structured hierarchy for better manageability.

Reading Time: 9 minutes

Introduction

Node.js and Express are powerful tools that simplify web application development. A standout feature of Express is its routing system, which lets you define how your app responds to HTTP requests. Routers take this a step further by allowing you to modularize your routes into separate files, making your codebase cleaner, more maintainable, and scalable. In this guide, we’ll walk through how to create and import routers in Node.js and Express, step by step.

What Are Routers in Node.js and Why Use Them?

Routers in Node.js, particularly with Express, are mini-applications that handle specific subsets of routes. Instead of cramming all your routes into one file, you can split them into logical groups—like user routes (/users) or product routes (/products). This modularity enhances organization and makes it easier to manage large applications.

How to Create a Router in Node.js and Express

Creating a router is straightforward and essential for keeping your project structured. Here’s how to do it:

Step 1: Set Up Your Node.js Project

Ensure Node.js is installed, then create and initialize a project:

				
					mkdir my-node-app
cd my-node-app
npm init -y

Step 2: Install Express

Install Express, the web framework that powers routing:

				
					npm install express --save

Step 3: Create a Router File

In your project directory, create a file like routes/myRouter.js:

				
					// routes/myRouter.js
const express = require('express');
const router = express.Router();

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

module.exports = router;

Here, express.Router() creates an independent router instance.

Step 4: Define Routes

Add specific routes to your router file. For example:

				
					// routes/myRouter.js
const express = require('express');
const router = express.Router();

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

router.get('/:id', (req, res) => {
    res.send(`Item ID: ${req.params.id}`);
});

module.exports = router;

Step 5: Use the Router in Your Application

In your main file (e.g., app.js), import and mount the router:

				
					// app.js
const express = require('express');
const app = express();
const myRouter = require('./routes/myRouter');

app.use('/api', myRouter); // Mounts router at /api

app.listen(3000, () => {
    console.log('Server running on port 3000');
});

Run node app.js, and visiting http://localhost:3000/api will display “Hello, World!” while http://localhost:3000/api/123 shows “Item ID: 123”.

How to Import a Router in Node.js

Importing a router is just as simple and builds on the creation process:

Step 1: Ensure a Router Exists

Follow the steps above to create a router if you haven’t already.

Step 2: Import and Mount the Router

In your main app file, require the router and use it:

				
					// app.js
const express = require('express');
const app = express();
const myRouter = require('./routes/myRouter');

app.use('/api', myRouter); // Routes prefixed with /api

app.listen(3000, () => {
    console.log('Server running on port 3000');
});

How to Organize Multiple Routers

For larger apps, you’ll likely need multiple routers. Here’s how to manage them:

Step 1: Create Additional Routers

Example: routes/users.js and routes/products.js:

				
					// routes/users.js
const express = require('express');
const router = express.Router();

router.get('/', (req, res) => {
    res.send('User list');
});

module.exports = router;

				
					// routes/products.js
const express = require('express');
const router = express.Router();

router.get('/', (req, res) => {
    res.send('Product list');
});

module.exports = router;

Step 2: Import and Mount in the Main App

Update app.js:

				
					// app.js
const express = require('express');
const app = express();
const userRouter = require('./routes/users');
const productRouter = require('./routes/products');

app.use('/users', userRouter);
app.use('/products', productRouter);

app.listen(3000, () => {
    console.log('Server running on port 3000');
});

Now, /users and /products are handled by their respective routers.

Enhancing Routers: Middleware and Error Handling

Adding Middleware: Apply middleware to a router for tasks like logging or authentication:

				
					router.use((req, res, next) => {
    console.log('Request received');
    next();
});

Error Handling: Add error-handling middleware:

				
					router.use((err, req, res, next) => {
    res.status(500).send('Something went wrong!');
});

Common Questions About Routers

What’s the difference between app.use() and router.get()?
app.use() mounts middleware or routers for all HTTP methods, while router.get() defines a route for GET requests only.
Can I nest routers?
Yes! Mount one router inside another using router.use() for deeper route hierarchies.

Conclusion

Routers in Node.js and Express are indispensable for building organized, scalable web applications. By creating modular routers and importing them into your project, you can keep your codebase clean and manageable. Whether you’re defining a single router or managing multiple ones, the steps in this guide will set you up for success in building robust applications with Node.js and Express.

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res.status(500).send(‘Something went wrong!’);

});

Can I have nested routers in Express?

Yes, routers can be nested using router.use(). This allows you to organize routes into a structured hierarchy for better manageability.

Creating and Importing Routers in Node.js

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