Book Image

Angular 2 Cookbook

By : Patrick Gillespie, Matthew Frisbie
Book Image

Angular 2 Cookbook

By: Patrick Gillespie, Matthew Frisbie

Overview of this book

Angular 2 introduces an entirely new way to build applications. It wholly embraces all the newest concepts that are built into the next generation of browsers, and it cuts away all the fat and bloat from Angular 1. This book plunges directly into the heart of all the most important Angular 2 concepts for you to conquer. In addition to covering all the Angular 2 fundamentals, such as components, forms, and services, it demonstrates how the framework embraces a range of new web technologies such as ES6 and TypeScript syntax, Promises, Observables, and Web Workers, among many others. This book covers all the most complicated Angular concepts and at the same time introduces the best practices with which to wield these powerful tools. It also covers in detail all the concepts you'll need to get you building applications faster. Oft-neglected topics such as testing and performance optimization are widely covered as well. A developer that reads through all the content in this book will have a broad and deep understanding of all the major topics in the Angular 2 universe.
Table of Contents (18 chapters)
Angular 2 Cookbook
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Dedication
Preface

Service injection aliasing with useClass and useExisting


As your application becomes more complex, you may come to a situation where you would like to use your services in a polymorphic style. More specifically, some places in your application may want to request Service A, but a configuration somewhere in your application will actually give it Service B. This recipe will demonstrate one way in which this can be useful, but this behavior allows your application to be more extensible in multiple ways.

Note

The code, links, and a live example of this are available at http://ngcookbook.herokuapp.com/1109/.

Getting ready

Suppose you begin with the following skeleton application.

Dual services

You begin with two services, ArticleService and EditorArticleService, and their shared interface, ArticleSourceInterface. EditorArticleService inherits from ArticleService:

[app/article-source.interface.ts] 
 
export interface ArticleSourceInterface { 
  getArticle():Article 
} 
 
...