Book Image

Angular Services

By : Sohail Salehi
Book Image

Angular Services

By: Sohail Salehi

Overview of this book

A primary concern with modern day applications is that they need to be dynamic, and for that, data access from the server side, data authentication, and security are very important. Angular leverages its services to create such state-of-the-art dynamic applications. This book will help you create and design customized services, integrate them into your applications, import third-party plugins, and make your apps perform better and faster. This book starts with a basic rundown on how you can create your own Angular development environment compatible with v2 and v4. You will then use Bootstrap and Angular UI components to create pages. You will also understand how to use controllers to collect data and populate them into NG UIs. Later, you will then create a rating service to evaluate entries and assign a score to them. Next, you will create "cron jobs" in NG. We will then create a crawler service to find all relevant resources regarding a selected headline and generate reports on it. Finally, you will create a service to manage accuracy and provide feedback about troubled areas in the app created. This book is up to date for the 2.4 release and is compatible with the 4.0 release as well, and it does not have any code based on the beta or release candidates.
Table of Contents (15 chapters)
Angular Services
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Angular and observable objects


If you look at the browser, you will find that the Collector page is empty and there are a bunch of errors in the console. That is because we are trying to work with Observable objects without including the related library into our project. In our Angular 2 seed project, there is a place for vendor packages:

src/vendor.browser.ts

Open this file and simply uncomment the line that imports the RxJS library:

// src/vendor.browser.ts 
// ... 
// RxJS 5 
import 'rxjs/Rx'; 
//... 

Now we can investigate how Observable objects work here. Checking the http object, the task of the get() method is obvious. It is a simple HTTP GET request and returns a response. But what about those map() functions? Where do they come from and what do they do? To answer that question, hold the Ctrl key (or command key if you are using Mac) in your IDE and click on the Http object inside the collector.service.ts. This will take you directly to the definition of the get() method inside the...