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 the switchMap operator to switch the last subscription with a new one

For a lot of apps, we have features such as searching content as the user types. This is a really good user experience (UX) as the user doesn't have to press a button to do a search. However, if we send a call to the server on every keyboard press, that's going to result in a lot of HTTP calls being sent, and we can't know which HTTP call will complete first; thus, we can't be sure if we will have the correct data shown on the view or not. In this recipe, you'll learn to use the switchMap operator to cancel out the last subscription and create a new one instead. This would result in canceling previous calls and keeping only one call—the last one.

Getting ready

The project that we are going to work with resides in chapter05/start_here/using-switchmap-operator, inside the cloned repository.

  1. Open the project in VS Code.
  2. Open the Terminal and run npm install to...