10 Best Practices for Optimizing Angular Performance

Optimizing the performance of your Angular application is crucial for providing a smooth user experience. Here are 10 best practices to help you get the most out of your Angular apps.

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1. OnPush Change Detection Strategy 🧠

By default, Angular uses the Default change detection strategy, which checks all components for changes. Using the OnPush strategy reduces the number of checks by only checking components when their inputs change.

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html',
  changeDetection: ChangeDetectionStrategy.OnPush
})
export class MyComponent {
  @Input() data: any;
}

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2. Use TrackBy with ngFor 🔄

Using trackBy in ngFor helps Angular identify items in a list, reducing the number of DOM manipulations.

<div *ngFor="let item of items; trackBy: trackByFn">
  {{ item.name }}
</div>

trackByFn(index, item) {
  return item.id;
}

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3. Lazy Loading Modules 📦

Lazy loading modules ensures that only the necessary parts of your application are loaded, reducing the initial load time.

const routes: Routes = [
  {
    path: 'feature',
    loadChildren: () => import('./feature/feature.module').then(m => m.FeatureModule)
  }
];

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4. Optimize Template Expressions 🖋️

Avoid complex calculations and function calls in template expressions. Instead, compute values in the component class and bind them to the template.

<!-- Instead of this -->
<div>{{ computeHeavyTask() }}</div>

<!-- Use this -->
<div>{{ computedValue }}</div>

ngOnInit() {
  this.computedValue = this.computeHeavyTask();
}

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5. Use AOT Compilation 🛠️

Ahead-of-Time (AOT) compilation pre-compiles your Angular templates and components, resulting in faster rendering and smaller bundle sizes.

ng build --prod --aot

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6. Optimize Styles and Scripts Loading 🎨

Load styles and scripts conditionally to reduce the initial load. Use ngStyle and ngClass for conditional styling.

<div [ngClass]="{'class-a': conditionA, 'class-b': conditionB}"></div>

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7. Use Pure Pipes for Data Transformation 📊

Pure pipes are stateless and only recalculate when their input arguments change, making them more efficient than impure pipes.

@Pipe({ name: 'purePipe', pure: true })
export class PurePipe implements PipeTransform {
  transform(value: any, ...args: any[]): any {
    // Transformation logic
  }
}

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8. Minimize the Use of Third-Party Libraries 📚

Only include necessary third-party libraries and remove unused ones. This reduces the bundle size and improves load times.

npm prune

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9. Optimize Images and Assets 🖼️

Use optimized images and lazy load them to improve performance. Tools like ImageOptim or online services can help reduce image sizes.

<img [src]="imageSrc" loading="lazy" />

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10. Avoid Memory Leaks 🧹

Unsubscribe from Observables and detach event listeners to prevent memory leaks.

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html'
})
export class MyComponent implements OnDestroy {
  private subscription: Subscription;

  ngOnInit() {
    this.subscription = this.myService.getData().subscribe();
  }

  ngOnDestroy() {
    this.subscription.unsubscribe();
  }
}

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Start Your JavaScript Journey

If you're new to JavaScript or want a refresher, visit my blog on BuyMeACoffee to get started with the basics.

👉 Introduction to JavaScript: Your First Steps in Coding

By following these best practices, you can optimize the performance of your Angular applications, providing a better experience for your users. Happy coding! 🚀

Series Index

Part	Title	Link
1	8 Exciting New JavaScript Concepts You Need to Know	Read
2	Top 7 Tips for Managing State in JavaScript Applications	Read
3	🔒 Essential Node.js Security Best Practices	Read
4	10 Best Practices for Optimizing Angular Performance	Read
5	Top 10 React Performance Optimization Techniques	Read
6	Top 15 JavaScript Projects to Boost Your Portfolio	Read
7	6 Repositories To Master Node.js	Read
8	Best 6 Repositories To Master Next.js	Read
9	Top 5 JavaScript Libraries for Building Interactive UI	Read
10	Top 3 JavaScript Concepts Every Developer Should Know	Read
11	20 Ways to Improve Node.js Performance at Scale	Read
12	Boost Your Node.js App Performance with Compression Middleware	Read
13	Understanding Dijkstra's Algorithm: A Step-by-Step Guide	Read
14	Understanding NPM and NVM: Essential Tools for Node.js Development	Read

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