4: Add Services

[examples/angular-tour-of-heroes] / src / app / hero.service.ts

import { Injectable } from '@angular/core';
import { Observable, of } from 'rxjs';
import { Hero } from './hero';
import { HEROES } from './mock-heroes';


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

  constructor() { }

  getHeroes() : Observable<Hero[]> {
    return of(HEROES);
  }
}