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Express Route Parameters – How To Use Route Parameters in Express.js
Express.js is a popular web framework for building web applications in Node.js. One of the key features of Express.js is its routing system, which allows developers to define routes and handle requests to those routes. In this article, we will learn about route parameters in Express.js and how to use them in your applications.
What are Route Parameters?
Route parameters are dynamic parts of a route URL that can capture values from incoming requests. They are denoted by a colon followed by the parameter name. For example, in the route ‘/users/:id’, ‘:id’ is a route parameter that can capture the value of the ‘id’ parameter from the URL.
How to Use Route Parameters in Express.js
Using route parameters in Express.js is straightforward. You can define route parameters in your route URLs and access them in your route handlers using the ‘req.params’ object. Here’s an example:
“`javascript
const express = require(‘express’);
const app = express();
// Define a route with a route parameter
app.get(‘/users/:id’, (req, res) => {
const userId = req.params.id;
res.send(`User ID: ${userId}`);
});
app.listen(3000, () => {
console.log(‘Server is running on port 3000’);
});
“`
In the above example, we define a route ‘/users/:id’ with a route parameter ‘:id’. When a request is made to this route, we can access the value of the ‘id’ parameter using ‘req.params.id’ and send a response with that value.
Using Multiple Route Parameters
You can also define routes with multiple parameters in Express.js. Simply add additional route parameters to your route URLs and access them in your route handlers. Here’s an example with multiple route parameters:
“`javascript
// Define a route with multiple route parameters
app.get(‘/products/:category/:id’, (req, res) => {
const category = req.params.category;
const productId = req.params.id;
res.send(`Category: ${category}, Product ID: ${productId}`);
});
“`
In this example, we have defined a route ‘/products/:category/:id’ with two route parameters ‘:category’ and ‘:id’. We can access the values of both parameters using ‘req.params.category’ and ‘req.params.id’ respectively.
Conclusion
Route parameters in Express.js are a powerful feature that allows you to make your routes more dynamic and flexible. By using route parameters, you can create routes that can capture and handle variable data from incoming requests. In this article, we learned how to use route parameters in Express.js and how to access them in route handlers. We also saw how to define routes with multiple parameters. I hope this article helps you understand how to use route parameters in Express.js in your own applications.
