req.params for route parameters in Express - Mini Project: Build & Apply

Using req.params for Route Parameters in Express

📖 Scenario: You are building a simple Express server that responds to user requests for product details. Each product has a unique ID.

🎯 Goal: Create an Express route that uses req.params to capture the product ID from the URL and send it back in the response.

📋 What You'll Learn

Create an Express app instance called app

Create a route with path /product/:id

Use req.params.id to get the product ID from the URL

Send a response with the text Product ID: <id> where <id> is the captured parameter

💡 Why This Matters

🌍 Real World

Web servers often need to get information from the URL to show specific data, like product details or user profiles.

💼 Career

Understanding how to use route parameters with <code>req.params</code> is essential for backend web development with Express.

1

Set up Express app

Create a variable called express that requires the 'express' module. Then create an Express app instance called app by calling express().

Express

const express = require('express');
const app = express();
// Your code here

Need a hint?

Use require('express') to import Express and then call it as a function to create the app.

2

Create route with parameter

Use app.get to create a route with path '/product/:id' and a callback function with parameters req and res.

Express

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

// Create GET route for '/product/:id'
// Your code here

Need a hint?

Use app.get with the path including :id to capture the parameter.

3

Access route parameter

Inside the route callback, create a variable called productId and set it to req.params.id to get the product ID from the URL.

Express

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

app.get('/product/:id', (req, res) => {
  // Get product ID from req.params
  // Your code here
});

Need a hint?

Use req.params.id to get the value of the :id parameter from the URL.

4

Send response with product ID

Use res.send to send the text `Product ID: ${productId}` as the response inside the route callback.

Express

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

app.get('/product/:id', (req, res) => {
  const productId = req.params.id;
  // Send response with product ID
  // Your code here
});

Need a hint?

Use template literals with backticks to include the productId variable in the response text.