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"; 
 
@Injectable() 
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 
  rateNews(){} 
} 

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...