use Map 來儲存 service

app.component.ts

import {Component, Inject, Injector} from '@angular/core';

import {serviceToken} from './app.module';
import {IService} from './iservice';
import {Service1Service} from './service1.service';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'app';
  private services = new Map<string, IService>();
  constructor(private injector: Injector) {
    (<IService[]>injector.get(serviceToken)).forEach(s => {
      this.services.set(s.kind, s);
    });
  }

  callFunction(kind: string): IService|undefined {
    return this.services.get(kind);
  }

  callService(kind: string) {
    const s = this.callFunction(kind);
    console.log(s.log());
  }
}