How can you use server-side rendering in a Node.js application, and what are its benefits? — Node.js Interview Question #59

Server-side rendering (SSR) is a technique where the server processes and generates an HTML page for the client, rather than relying on the client to render the page using JavaScript. In a Node.js application, this can be achieved using various libraries and frameworks like Express and Next.js. The main benefits of SSR include faster initial page load times, better SEO, and improved performance on low-powered devices. In this answer, we will discuss how to use SSR in an Express application and its benefits.

To implement server-side rendering in a Node.js application using the Express framework, you can use template engines like EJS, Pug, or Handlebars. Here’s an example of how to set up a simple Express application with server-side rendering using the EJS template engine:

1. First, install Express and EJS:

npm install express ejs

2. Create a new file called ‘app.js‘ and add the following code to set up a basic Express application with EJS as the template engine:

const express = require('express');
const ejs = require('ejs');
const app = express();
const PORT = process.env.PORT || 3000;

// Set EJS as the template engine
app.set('view engine', 'ejs');

// Define a route to render the EJS template
app.get('/', (req, res) => {
  const data = { title: 'Server-side Rendering Example' };
  res.render('index', data);
});

// Start the server
app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});

3. Create a new folder called ‘views‘ and inside that folder, create an EJS file called ‘index.ejs‘ with the following content:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title><%= title %></title>
</head>
<body>
  <h1><%= title %></h1>
  <p>This is an example of server-side rendering using Node.js and EJS.</p>
</body>
</html>

4. Start your server by running ‘node app.js‘, and then navigate to ‘http://localhost:3000‘ in your browser. You will see the rendered HTML page sent from the server.

Now let’s discuss the benefits of server-side rendering:

1. **Faster initial page load times**: With SSR, the browser gets a fully rendered HTML page from the server instead of waiting for the JavaScript to be downloaded, parsed, and executed on the client-side. This results in a faster loading of the initial content, giving users a better experience, especially on slow connections.

2. **Better SEO**: SSR also improves a website’s search engine optimization (SEO) since search engine crawlers can more easily parse and index the content of a server-rendered page. Some crawlers have limited support for processing client-side JavaScript, so relying on client-side rendering could negatively impact a website’s SEO performance.

3. **Improved performance on low-powered devices**: SSR offloads some of the computational burden from the client to the server. This allows users on devices with limited processing power (e.g., older smartphones) to experience faster and smoother website interactions.

Keep in mind that SSR can also introduce some complexities in terms of performance, state management, and caching, so it’s important to consider the specific requirements of your application when deciding whether to use server-side rendering.

To conclude, server-side rendering in a Node.js application can help you deliver a faster, more performant experience for your users, and improve your site’s SEO. This can be achieved using an Express application with template engines like EJS, Pug, or Handlebars. Alternatively, you can explore more advanced frameworks like Next.js for more powerful SSR capabilities and features.