import { Component } from '@angular/core';
import { Observable } from 'rxjs/Rx';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  online$: Observable<boolean>;
  constructor(){
      this.online$ = Observable.merge(
        Observable.of(navigator.onLine),
        Observable.fromEvent(window, 'online').map(() => true),
        Observable.fromEvent(window, 'offline').map(() => false)
      )
  }

}