Angular Universal: Server-Side Rendering for Angular Applications

Angular Universal is a technology that enables server-side rendering (SSR) for Angular applications. SSR improves performance, SEO, and user experience by rendering Angular applications on the server and sending fully-rendered HTML to the client. In this article, we’ll explore what Angular Universal is, how it works, and how to implement it in your Angular applications. By the end of this guide, you’ll have a solid understanding of how to use Angular Universal to build high-performance, SEO-friendly applications.

What is Angular Universal?

Angular Universal is a framework for server-side rendering (SSR) in Angular applications. It allows you to render Angular components on the server and send fully-rendered HTML to the client. This approach provides several benefits:

• Improved Performance: SSR reduces the time to first meaningful paint, improving the perceived performance of your application.
• Better SEO: Search engines can crawl and index server-rendered content more effectively, improving your application’s search engine ranking.
• Enhanced User Experience: Users see content faster, even on slow devices or networks.

How Does Angular Universal Work?

Angular Universal works by running your Angular application on the server and generating static HTML for the initial page load. Once the HTML is sent to the client, Angular takes over and bootstraps the application, enabling interactivity.

Key Concepts

• Server-Side Rendering (SSR): The process of rendering Angular components on the server and sending HTML to the client.
• Client-Side Hydration: The process of bootstrapping the Angular application on the client after the initial HTML is rendered.
• Universal Engine: The engine that enables Angular applications to run on the server.

Setting Up Angular Universal

Let’s walk through the process of setting up Angular Universal in an existing Angular application.

Step 1: Install Angular Universal

Use the Angular CLI to add Angular Universal to your project:

ng add @nguniversal/express-engine

This command installs the necessary packages and configures your application for server-side rendering.

Step 2: Modify the Server Configuration

The Angular CLI generates a server.ts file, which configures the Express server for SSR. You can customize this file to suit your needs.

import 'zone.js/dist/zone-node';
import { ngExpressEngine } from '@nguniversal/express-engine';
import * as express from 'express';
import { join } from 'path';
import { AppServerModule } from './src/main.server';

const app = express();
const distFolder = join(process.cwd(), 'dist/browser');

app.engine('html', ngExpressEngine({
  bootstrap: AppServerModule,
}));

app.set('view engine', 'html');
app.set('views', distFolder);

app.get('*.*', express.static(distFolder));

app.get('*', (req, res) => {
  res.render('index', { req });
});

app.listen(4000, () => {
  console.log('Server listening on http://localhost:4000');
});

Step 3: Build and Run the Application

Build the application for server-side rendering:

npm run build:ssr

Run the server:

npm run serve:ssr

Your application will now be available at http://localhost:4000 with server-side rendering enabled.

Best Practices for Angular Universal

Here are some best practices for using Angular Universal:

• Optimize Performance: Minimize the size of your application bundle to improve server-side rendering performance.
• Use TransferState: Use the TransferState API to transfer data from the server to the client, reducing duplicate API calls.
• Handle Browser-Specific Code: Use the isPlatformBrowser and isPlatformServer functions to handle browser-specific code.

Secrets and Hidden Facts

• Pre-rendering: Use Angular Universal to pre-render static pages for improved performance and SEO.
• Dynamic Rendering: Use Angular Universal to dynamically render pages based on user input or other conditions.
• Third-Party Libraries: Some third-party libraries may not work with Angular Universal. Use the @nguniversal/common package to handle compatibility issues.

Conclusion

Angular Universal is a powerful tool for improving the performance, SEO, and user experience of Angular applications. By enabling server-side rendering, you can deliver fully-rendered HTML to the client, reducing load times and improving search engine rankings. Whether you’re building a small application or a large enterprise solution, Angular Universal is an essential tool for modern web development.

So, start using Angular Universal in your projects and unlock the full potential of Angular!