Angular2 Message Service

<!DOCTYPE html>
<html>

  <head>
    <base href="." />
    <title>angular2 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 */
sender, receiver {
  float: left;
  width: 45%;
}

### Angular Starter Plunker - Typescript

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/bundles/core.umd.js',
    '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
    '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
    '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
    '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
    '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
    '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
    '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',
    
    '@angular/core/testing': 'npm:@angular/core/bundles/core-testing.umd.js',
    '@angular/common/testing': 'npm:@angular/common/bundles/common-testing.umd.js',
    '@angular/compiler/testing': 'npm:@angular/compiler/bundles/compiler-testing.umd.js',
    '@angular/platform-browser/testing': 'npm:@angular/platform-browser/bundles/platform-browser-testing.umd.js',
    '@angular/platform-browser-dynamic/testing': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic-testing.umd.js',
    '@angular/http/testing': 'npm:@angular/http/bundles/http-testing.umd.js',
    '@angular/router/testing': 'npm:@angular/router/bundles/router-testing.umd.js',
    
    'rxjs': 'npm:rxjs',
    'typescript': 'npm:typescript@2.0.2/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';

platformBrowserDynamic().bootstrapModule(AppModule)

//our root app component
import {Component, NgModule} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'
import {MessageService} from './message.service'
import {SenderComponent } from './sender.component'
import {ReceiverComponent } from './receiver.component'

@Component({
  selector: 'my-app',
  template: `
    <sender></sender>
    <receiver></receiver>
  `,
  providers: [MessageService]
})
export class App {
  name:string;
  constructor() {
    this.name = 'Angular2'
  }
}

@NgModule({
  imports: [ BrowserModule ],
  declarations: [ App, SenderComponent, ReceiverComponent ],
  bootstrap: [ App ]
})
export class AppModule {}

import { Injectable } from '@angular/core';
import { Subject } from 'rxjs/Subject';
import { Subscription } from 'rxjs/Subscription';
import 'rxjs/add/operator/filter'
import 'rxjs/add/operator/map'

interface Message {
  type: string;
  payload: any;
}

type MessageCallback = (payload: any) => void;

@Injectable()
export class MessageService {
  private handler = new Subject<Message>();

  broadcast(type: string, payload: any) {
    this.handler.next({ type, payload });
  }

  subscribe(type: string, callback: MessageCallback): Subscription {
    return this.handler
      .filter(message => message.type === type)
      .map(message => message.payload)
      .subscribe(callback);
  }
}

import {Component, OnDestroy} from '@angular/core'
import {MessageService} from './message.service'
import {Subscription} from 'rxjs/Subscription'

@Component({
  selector: 'sender',
  template: `
    <h3>Sender
      <button (click)="toggleSubscribed()">
        {{unsubscribed && 'Subscribe' || 'Unsubscribe'}}
      </button>
    </h3>
    <button (click)="send()">Send Message</button>
    <h4 *ngIf="messages.length">
      Incoming Messages
      <button (click)="clear()">x</button>
    </h4>
    <ul>
      <li *ngFor="let message of messages">Response: {{message}}</li>
    </ul>
  `,
  styles: [`
    button {
      outline: none;
    }
    h3 button {
      background-color: inherit;
      border: none;
      text-decoration: underline;
      cursor: pointer;
    }
    h3 button:active {
      text-decoration: none;
    }
    ul {
      list-style: none;
      padding-left: 8px;
    }
  `]
})
export class SenderComponent implements OnDestroy {
  private subscription: Susbcription;
  private messages = [];
  private messageNum = 0;
  private name = 'sender'
  
  constructor(private messageService: MessageService) {
    this.subscribe();
  }
  
  get unsubscribed() {
    return this.subscription && this.subscription.closed;
  }
  
  send() {
    let payload = {
      text: `Message ${++this.messageNum}`,
      respondEvent: this.name
    }
    this.messageService.broadcast('receiver', payload);
  }
  
  clear() {
    this.messages = [];
  }
  
  subscribe() {
    this.subscription = this.messageService.subscribe('sender', (payload) => {
      this.messages.push(payload);
    });
    
  }
  
  unsubscribe() {
    this.subscription.unsubscribe();
  }
  
  toggleSubscribed() {
    if (this.unsubscribed {
      this.subscribe();
    } else {
      this.unsubscribe();
    }
  }
  
  ngOnDestroy() {
    unsubscribe();
  }
}

import {Component, OnDestroy} from '@angular/core'
import {MessageService} from './message.service'
import {Subscription} from 'rxjs/Subscription'

@Component({
  selector: 'receiver',
  template: `
    <h3>Receiver
      <button (click)="toggleSubscribed()">
        {{unsubscribed && 'Subscribe' || 'Unsubscribe'}}
      </button>
    </h3>
    <h4 *ngIf="messages.length">
      Incoming Messages
      <button (click)="clear()">x</button>
    </h4>
    <ul>
      <li *ngFor="let message of messages">
        {{message.text}}
        <button (click)="send(message)">Respond</button>
      </li>
    </ul>
  `,
  styles: [`
    button {
      outline: none;
    }
    h3 button {
      background-color: inherit;
      border: none;
      text-decoration: underline;
    }
    h3 button:active {
      text-decoration: none;
    }
    ul {
      list-style: none;
      padding-left: 8px;
    }
  `]
})
export class ReceiverComponent implements OnDestroy {
  private subscription: Susbcription;
  private messages = [];
  
  constructor(private messageService: MessageService) {
    this.subscribe();
  }
  
  get unsubscribed() {
    return this.subscription && this.subscription.closed;
  }
  
  send(message: {text: string, respondEvent: string}) {
    this.messageService.broadcast(message.respondEvent, message.text);
  }
  
  clear() {
    this.messages = [];
  }
  
  subscribe() {
    this.subscription = this.messageService.subscribe('receiver', (payload) => {
      this.messages.push(payload);
    });
    
  }
  
  unsubscribe() {
    this.subscription.unsubscribe();
  }
  
  toggleSubscribed() {
    if (this.unsubscribed {
      this.subscribe();
    } else {
      this.unsubscribe();
    }
  }
  
  ngOnDestroy() {
    unsubscribe();
  }
}