Injectable services

Another key building block of Angular services. Following Angular's architecture, services are supposed to encapsulate business logic and application-wide states. Additionally, services are useful to bridge between different components that aren't necessarily a direct parent and child.

As this is your first services-related task, extract the categories data to an Angular service.

First, generate the CategoriesServiceservice, as part of the CoreModule, by executing the following command:

ng generate service modules/core/services/categories

Afterward, the service is created in a file named categories.service.ts, containing the following content:

import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root'
})
export class CategoriesService {
  constructor() { }
}

As you can see, services in Angular are simply classes decorated with an @Injectable decorator.

Angular provides a dependency injection solution, which eases the use of services in your app. Dependency...