angular-docs-cn/public/docs/_examples/architecture/ts/app/hero.service.ts

import {Injectable} from '@angular/core';
import {Hero} from './hero';
import {BackendService} from './backend.service';
import {Logger} from './logger.service';

@Injectable()
// #docregion class
export class HeroService {
  // #docregion ctor
  constructor(
    private _backend: BackendService,
    private _logger: Logger) { }
  // #enddocregion ctor

  private _heroes: Hero[] = [];

  getHeroes() {
    this._backend.getAll(Hero).then( (heroes: Hero[]) => {
      this._logger.log(`Fetched ${heroes.length} heroes.`);
      this._heroes.push(...heroes); // fill cache
    });
    return this._heroes;
  }
}
// #enddocregion class