Discover how to render dynamic HTML content in Express, a popular web application framework for Node.js. Learn about setting up a templating engine, such as Handlebars, defining routes, passing data to templates, and leveraging layout templates for reusable page structures. Gain a comprehensive understanding of rendering HTML from endpoints in Express for building dynamic and interactive web applications.
In Express, rendering HTML from endpoints is a fundamental task for creating dynamic web applications. It involves generating HTML content dynamically on the server and sending it as a response to the client’s request. Express provides several methods and techniques to facilitate this process and make rendering HTML from endpoints seamless and efficient.
To begin rendering HTML, developers first need to set up their Express application and define the necessary routes. Express uses a templating engine to generate HTML dynamically, and one popular option is Handlebars. Start by installing the Handlebars package via npm:
npm install express-handlebars
Once installed, configure the Handlebars templating engine in your Express application:
const express = require('express');
const exphbs = require('express-handlebars');
const app = express();
// Configure Handlebars as the view engine
app.engine('handlebars', exphbs());
app.set('view engine', 'handlebars');
With Handlebars set up, you can define a route that renders an HTML template. Create a views folder in your project directory and add a Handlebars template file, for example, home.handlebars, with the desired HTML structure:
<!DOCTYPE html> <html> <head> <title>My Express App</title> </head> <body> <h1>Welcome to my Express app!</h1> </body> </html>
To render this template from an endpoint, define the route handler and use the res.render() method:
app.get('/', (req, res) => {
res.render('home');
});
In the example above, when a GET request is made to the root URL (“/”), the home.handlebars template will be rendered and sent as the response. Express automatically looks for templates in the views folder based on the view engine configuration.
Handlebars templates can also accept dynamic data for rendering. For instance, you can pass an object containing variables to be used within the template. Modify the route handler as follows:
app.get('/user/:id', (req, res) => {
const user = {
id: req.params.id,
name: 'John Doe',
age: 28
};
res.render('user', { user });
});
In this case, a route is defined with a parameter id for the user. The user.handlebars template will be rendered, and the user object will be accessible within the template for dynamic rendering.
Additionally, Express provides the ability to use layout templates that define the common structure for multiple pages. This allows for reusable header, footer, or navigation sections across different views. To use layouts with Handlebars, modify the view engine configuration:
app.engine('handlebars', exphbs({ defaultLayout: 'main' }));
Here, a layout template named main.handlebars is specified as the default layout for all views. Inside the layout template, use the {{{ body }}} placeholder to indicate where the content from each specific view should be inserted.
Rendering HTML from endpoints in Express is a powerful feature that allows developers to generate dynamic web content efficiently. By using a templating engine like Handlebars, developers can separate the HTML structure from the dynamic data, enabling flexible and maintainable code. Express simplifies the process of rendering templates, making it easy to send dynamic HTML responses to clients based on their requests.
