Performance Optimization in Angular Applications

Angular provides powerful tools for building high-performance applications. Let's explore strategies to optimize your Angular applications for speed and efficiency.

Understanding Change Detection

Angular's change detection is automatic, but understanding how it works can help you optimize:

@Component({
  selector: 'app-user-list',
  changeDetection: ChangeDetectionStrategy.OnPush,
  template: `...`
})
export class UserListComponent {
  users$ = this.userService.getUsers();
}

Using OnPush change detection strategy reduces unnecessary checks and improves performance.

Lazy Loading Modules

Implement lazy loading to split your application into smaller chunks:

const routes: Routes = [
  {
    path: 'dashboard',
    loadChildren: () => import('./dashboard/dashboard.module').then(m => m.DashboardModule)
  },
  {
    path: 'settings',
    loadChildren: () => import('./settings/settings.module').then(m => m.SettingsModule)
  }
];

TrackBy Functions

Use trackBy functions when rendering lists to help Angular identify items:

trackByUserId(index: number, user: User): number {
  return user.id;
}

<div *ngFor="let user of users; trackBy: trackByUserId">
  {{ user.name }}
</div>

Optimizing Bundle Size

1. Use Angular CLI's production build: ng build --configuration production

2. Enable AOT compilation

3. Use tree-shaking to remove unused code

4. Consider using standalone components

Memory Leaks Prevention

Always unsubscribe from observables:

export class UserComponent implements OnDestroy {
  private destroy$ = new Subject<void>();
  
  constructor(private userService: UserService) {
    this.userService.getUsers()
      .pipe(takeUntil(this.destroy$))
      .subscribe(users => {
        // Handle users
      });
  }
  
  ngOnDestroy() {
    this.destroy$.next();
    this.destroy$.complete();
  }
}

Conclusion

Performance optimization in Angular requires understanding the framework's architecture and applying best practices consistently throughout your application.