Subscribe to events in a different component with Angular 4

<!DOCTYPE html>
<html>

  <head>
    <base href="." />
    <script type="text/javascript" charset="utf-8">
      window.AngularVersionForThisPlunker = 'latest'
    </script>
    <title>angular playground</title>
    <link rel="stylesheet" href="style.css" />
    <script src="https://unpkg.com/core-js@2.4.1/client/shim.min.js"></script>
    <script src="https://unpkg.com/zone.js/dist/zone.js"></script>
    <script src="https://unpkg.com/zone.js/dist/long-stack-trace-zone.js"></script>
    <script src="https://unpkg.com/reflect-metadata@0.1.3/Reflect.js"></script>
    <script src="https://unpkg.com/systemjs@0.19.31/dist/system.js"></script>
    <script src="config.js"></script>
    <script>
    System.import('app')
      .catch(console.error.bind(console));
  </script>
  </head>

  <body>
    <my-app>
    loading...
  </my-app>
  </body>

</html>

/* Styles go here */

### Angular Starter Plunker - Typescript

var angularVersion;
if(window.AngularVersionForThisPlunker === 'latest'){
  angularVersion = ''; //picks up latest
}
else {
  angularVersion = '@' + window.AngularVersionForThisPlunker;
}

System.config({
  //use typescript for compilation
  transpiler: 'typescript',
  //typescript compiler options
  typescriptOptions: {
    emitDecoratorMetadata: true
  },
  paths: {
    'npm:': 'https://unpkg.com/'
  },
  //map tells the System loader where to look for things
  map: {
    
    'app': './src',
    '@angular/core': 'npm:@angular/core'+ angularVersion + '/bundles/core.umd.js',
    '@angular/common': 'npm:@angular/common' + angularVersion + '/bundles/common.umd.js',
    '@angular/compiler': 'npm:@angular/compiler' + angularVersion  + '/bundles/compiler.umd.js',
    '@angular/platform-browser': 'npm:@angular/platform-browser' + angularVersion + '/bundles/platform-browser.umd.js',
    '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic' + angularVersion + '/bundles/platform-browser-dynamic.umd.js',
    '@angular/http': 'npm:@angular/http' + angularVersion + '/bundles/http.umd.js',
    '@angular/router': 'npm:@angular/router' + angularVersion +'/bundles/router.umd.js',
    '@angular/forms': 'npm:@angular/forms' + angularVersion + '/bundles/forms.umd.js',
    '@angular/animations': 'npm:@angular/animations' + angularVersion + '/bundles/animations.umd.js',
    '@angular/platform-browser/animations': 'npm:@angular/platform-browser' + angularVersion + '/bundles/platform-browser-animations.umd.js',
    '@angular/animations/browser': 'npm:@angular/animations' + angularVersion + '/bundles/animations-browser.umd.js',
    
    '@angular/core/testing': 'npm:@angular/core' + angularVersion + '/bundles/core-testing.umd.js',
    '@angular/common/testing': 'npm:@angular/common' + angularVersion + '/bundles/common-testing.umd.js',
    '@angular/compiler/testing': 'npm:@angular/compiler' + angularVersion + '/bundles/compiler-testing.umd.js',
    '@angular/platform-browser/testing': 'npm:@angular/platform-browser' + angularVersion + '/bundles/platform-browser-testing.umd.js',
    '@angular/platform-browser-dynamic/testing': 'npm:@angular/platform-browser-dynamic' + angularVersion + '/bundles/platform-browser-dynamic-testing.umd.js',
    '@angular/http/testing': 'npm:@angular/http' + angularVersion + '/bundles/http-testing.umd.js',
    '@angular/router/testing': 'npm:@angular/router' + angularVersion + '/bundles/router-testing.umd.js',
    'tslib': 'npm:tslib@1.6.1',
    'rxjs': 'npm:rxjs',
    'typescript': 'npm:typescript@2.2.1/lib/typescript.js'
  },
  //packages defines our app package
  packages: {
    app: {
      main: './main.ts',
      defaultExtension: 'ts'
    },
    rxjs: {
      defaultExtension: 'js'
    }
  }
});

//main entry point
import {platformBrowserDynamic} from '@angular/platform-browser-dynamic';
import {AppModule} from './app.module';

platformBrowserDynamic().bootstrapModule(AppModule)

import {Component, OnInit, VERSION} from '@angular/core'
import { LoginService } from './login.service'

@Component({
  selector: 'my-app',
  templateUrl: './src/app.component.html',
})
export class App implements OnInit {
  user
  
  constructor(
    loginService: LoginService
  ) {
    this.angularVersion = `Angular version ${VERSION.full}`
  }
  
  ngOnInit() {
    console.log('Init')
    // subscribe to a merge of loginService.logIn and loginService.logOut
  }
}

import {BrowserModule} from '@angular/platform-browser'
import {NgModule} from '@angular/core'
import { HttpModule } from '@angular/http'

import { App } from './app.component'

import { LoginComponent } from './login.component'
import { LoginService } from './login.service'

@NgModule({
  imports: [
    BrowserModule,
    HttpModule
  ],
  declarations: [
    App,
    LoginComponent
  ],
  providers: [
    LoginService
  ],
  bootstrap: [ App ]
})
export class AppModule {}

<div>
  <span>Logged in as <b>user.name</b></span><span>Not logged in</span>
  <h2>Shared services</h2><p>Created with {{angularVersion}}</p>
  <hr>
  <app-login></app-login>
</div>

import { Component } from '@angular/core'

import { LoginService } from './login.service'

@Component({
  selector: 'app-login',
  templateUrl: './src/login.component.html'
})
export class LoginComponent {
  user
  constructor(
    private loginService: LoginService
  ) {}
  
  logIn() {
    this.loginService.logIn().subscribe((user) => {
      console.log('Logged in')
      this.user = user
      console.log(this.user)
    )
  }
  
  logOut() {
    this.loginService.logOut().subscribe(() => console.log('Logged out'))
  }
}

<button (click)="logIn()">Log in</button>
<button (click)="logOut()">Log out</button>

import { Injectable } from '@angular/core'
import { Http } from '@angular/http'

import 'rxjs/add/operator/map'

@Injectable()
export class LoginService {
  private apiUrl = 'https://api.github.com/users/geraintanderson'

  constructor(
    private http: Http
  ) {}
  
  logIn() {
    return this.http
    .get(this.apiUrl)
    .map(response => response.json())
  }
  
  logOut() {
    return Observable.of(null)
  }
}