Book Image

Angular Cookbook

By : Muhammad Ahsan Ayaz
Book Image

Angular Cookbook

By: Muhammad Ahsan Ayaz

Overview of this book

The Angular framework, powered by Google, is the framework of choice for many web development projects built across varying scales. It’s known to provide much-needed stability and a rich tooling ecosystem for building production-ready web and mobile apps. This recipe-based guide enables you to learn Angular concepts in depth using a step-by-step approach. You’ll explore a wide range of recipes across key tasks in web development that will help you build high-performance apps. The book starts by taking you through core Angular concepts such as Angular components, directives, and services to get you ready for building frontend web apps. You’ll develop web components with Angular and go on to cover advanced concepts such as dynamic components loading and state management with NgRx for achieving real-time performance. Later chapters will focus on recipes for effectively testing your Angular apps to make them fail-safe, before progressing to techniques for optimizing your app’s performance. Finally, you’ll create Progressive Web Apps (PWA) with Angular to provide an intuitive experience for users. By the end of this Angular book, you’ll be able to create full-fledged, professional-looking Angular apps and have the skills you need for frontend development, which are crucial for an enterprise Angular developer.
Table of Contents (15 chapters)

Using trackBy for lists with *ngFor

Lists are an essential part of most of the apps we build today. If you're building an Angular app, there's a great chance you will use the *ngFor directive at some point. We know that *ngFor allows us to loop over arrays or objects generating HTML for each item. However, for large lists, using it may cause performance issues, especially when the source for *ngFor is changed completely. In this recipe, we'll learn how we can improve the performance of lists using the *ngFor directive with the trackBy function. Let's get started.

Getting ready

The project for this recipe resides in Chapter12/start_here/using-ngfor-trackb:

  1. Open the project in VS Code.
  2. Open the terminal and run npm install to install the dependencies of the project.
  3. Run the ng serve -o command to start the Angular app and serve it on the browser. You should see the app, as follows:

Figure 12.16 – App using-ngfor...