Angular: 14 Important tips to optimizing your code performance

Optimizing code performance in Angular can involve a range of techniques and strategies. Here are some tips for optimizing code performance in Angular:

1. Use OnPush change detection strategy: The OnPush change detection strategy helps reduce the number of change detection cycles, which can significantly improve the performance of your Angular application. By using OnPush, you can explicitly tell Angular to only perform change detection when the input properties to a component have changed.

2. Use lazy loading: Lazy loading is a technique that allows you to load parts of your Angular application on-demand, rather than loading everything at once. This can help reduce the initial load time of your application and improve its performance.

3. Use trackBy for ngFor loops: When rendering a list of items using ngFor, use trackBy to let Angular know which items have changed. This can help reduce the number of DOM updates that Angular needs to make.

4. Use Angular Universal: Angular Universal is a tool that allows you to render your Angular application on the server, which can help improve its performance by reducing the time it takes to load the initial page.

5. Minimize the use of ngIf: The ngIf directive can significantly impact the performance of your Angular application, especially when used in large lists. Try to minimize its use and consider using the ngSwitch directive instead.

6. Use production builds: When building your Angular application for production, use the --prod flag to enable production mode, which can help reduce the size of your application and improve its performance.

7. Use AOT compilation: Ahead-of-Time (AOT) compilation can help improve the performance of your Angular application by reducing the amount of code that needs to be downloaded and compiled by the browser.

8. Use pure pipes: When creating custom pipes in Angular, use pure pipes whenever possible. Pure pipes are only executed when their input data changes, which can help reduce the amount of processing required.

9. Use ChangeDetectionStrategy.OnPush with immutable data: When using OnPush, it's important to make sure that the data you're binding to your component is immutable. Immutable data means that the values cannot be changed after they are created. This can help Angular optimize change detection by comparing object references instead of deep object comparisons.

10. Use async pipe for Observable data: When binding to Observables in your template, use the async pipe instead of subscribing to the Observable in your component code. The async pipe can help reduce the amount of manual change detection you need to do, which can improve the performance of your application.

11. Use ngZone.runOutsideAngular() for long-running tasks: When running long-running tasks in your Angular application, use the ngZone.runOutsideAngular() method to execute the task outside of the Angular zone. This can help avoid triggering change detection cycles unnecessarily and improve the performance of your application.

12. Optimize image loading: Loading images can be a performance bottleneck in your Angular application. Consider optimizing image loading by using lazy loading, progressive loading, or by compressing images to reduce their file size.

13 Minimize HTTP requests: Minimizing the number of HTTP requests your application makes can significantly improve its performance. Consider combining and minifying your scripts and styles, and using a CDN to host static assets.

14. Use ng-content for reusable components: When creating reusable components in Angular, consider using the ng-content directive to allow for flexible and dynamic content projection. This can help reduce the amount of component duplication and improve the performance of your application.

By following these tips, you can significantly improve the performance of your Angular application and provide a better user experience for your customers. Remember that performance optimization is an iterative process, so keep monitoring and measuring the performance of your application, and continue to optimize it as necessary.