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
About the Author
About the Reviewer
Customer Feedback

The rating service structure

To make the development clear and easy, let's create the service class with empty methods and implement them as we proceed.

Head to the /rating folder inside your source code and create a new class as follows:

// src/app/rating/rating.service.ts 
import {Injectable} from "@angular/core"; 
export class RatingService { 
  //ToDo: construct the service object 
  constructor() {} 
  //ToDo: get the collected news from Firebase db 
  getNews() {} 
  //ToDo: get the latest trends to show them inside the template 
  getTrends() {} 
  //ToDo: rate the news based on constructed rules 

The first thing that we need to take care of is the business logic that we are going to use for rating. As we discussed before, the news date and number of important keywords are what we are going to begin with. This business logic will live in its own class (Separation of Concerns). That means if it was required to change or add more rating items...