Advanced Routing in Express.JS

Back to Express.js
Arjit Sharma
01 Min

As your application grows, organizing routes in a single file can quickly become unmanageable. To solve this, Express provides a Router object, allowing us to modularize routes into separate files for better structure and scalability.

What is express.Router()

The express.Router() function creates a new router instance. Think of it as a mini Express app that can handle its own routes and middleware. You can define routes in separate files and then plug them into your main application.

Example of User Routes

Let’s create a dedicated router for user-related endpoints to demonstrate express.Router working.

Creating a user router

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

// Define routes
router.get("/", (req, res) => res.send("User list"));
router.get("/:id", (req, res) => res.send(`User ${req.params.id}`));
router.post("/", (req, res) => res.send("User created"));

module.exports = router;

Here:

  • router.get(”/”) → Handles requests to /users/
  • router.get(”/:id”) → Handles requests to /users/:id
  • router.post(”/”) → Handles requests to create a new user

Integrating user router in main app

Now, import and use this router in your main application file

// app.js
const express = require("express");
const app = express();
const userRoutes = require("./routes/users");

// Mount the router
app.use("/users", userRoutes);

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

With this setup:

  • Visiting /users → Returns “User list”
  • Visiting /users/42 → Returns “User 42”
  • Posting to /users → Returns “User created”

Benefits of Modular Routing

  • Separation of concerns → Each feature has its own route file.
  • Scalability → Easier to add new modules without cluttering app.js.
  • Maintainability → Debugging and testing routes becomes simpler.
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