Angular Performance: From Laggy to Lightning Fast
Tags: angular, webdev, typescript, javascript
Published: 2024-04-24 06:04:16

Angular, one of the most popular front-end frameworks, empowers developers to build robust web applications. However, as applications grow in complexity, ensuring optimal performance becomes paramount. In this post, we'll explore various optimization techniques in Angular to enhance the performance and efficiency of your applications.

### Lazy Loading:
Lazy loading asynchronously loads modules or components when required, rather than loading everything upfront. This significantly improves initial loading time, especially for large projects. Angular provides built-in support for lazy loading using the `loadChildren` property in the routing configuration.

```javascript
const routes: Routes = [
  { path: 'lazy', loadChildren: () => import('./lazy/lazy.module').then(m => m.LazyModule) }
];

```

### Ahead-of-Time (AOT) Compilation:
AOT compilation converts Angular HTML and TypeScript code into efficient JavaScript during the build process, leading to smaller bundle sizes and faster rendering. By default, Angular CLI uses AOT compilation for production builds. When you run the `ng build --prod` command, Angular CLI automatically enables AOT compilation along with other production optimizations. Here's the command to enable AOT compilation explicitly

```cli
ng build --prod
```

### Tree Shaking:
Tree shaking eliminates unused code from your application's bundle during the build process. Angular CLI automatically performs tree shaking, but organizing imports and using ES6 module syntax can further optimize your code.

### Optimizing Change Detection:
Use techniques like OnPush change detection strategy and immutable data structures to optimize change detection and minimize unnecessary DOM updates.

```javascript
@Component({
  selector: 'app-example',
  templateUrl: './example.component.html',
  changeDetection: ChangeDetectionStrategy.OnPush
})

```

### Bundle Size Optimization:
Reduce bundle size by employing code splitting, minification, and compression techniques.

```json
"build": {
  "configurations": {
    "production": {
      "optimization": true
    }
  }
}
```
### Server-Side Rendering (SSR):
Server-Side Rendering (SSR) is a technique used to render web pages on the server before sending them to the client's browser. In traditional single-page applications (SPAs), the entire application logic runs in the client's browser, and the server sends only static HTML, CSS, and JavaScript files. However, with SSR, the server generates the HTML content dynamically and sends pre-rendered HTML to the client, improving performance, SEO, and user experience. [Click here to see SSR implementation](https://dev.to/keshavkhatri/implementing-angular-server-side-rendering-ssr-aka-angular-universal-1j0a)

### Production Mode:
Enabling production mode optimizes Angular applications by disabling development-specific features. Use the `--prod` flag when building your application using Angular CLI.

### Summary
Optimizing Angular applications for performance and efficiency is crucial for delivering a seamless user experience. By incorporating lazy loading, AOT compilation, tree shaking, production mode, optimizing change detection, bundle size optimization, and SSR techniques, you can significantly enhance the performance of your Angular applications.