Angular 2 Service Example 2: Service sharing data between two components

<!DOCTYPE html>
<html>

  <head>
    <base href="." />
    <title>angular2 playground</title>
    <link rel="stylesheet" href="style.css" />
    <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 */

### Angular2 Starter Plunker - Typescript - RC.0

A simple plunker demonstrating Angular2 usage:
- Uses SystemJS + TypeScript to compile on the fly
- Includes binding, directives, http, pipes, and DI usage.

For opening

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 { CountService }      from './count.service';

import { FooComponent }      from './foo.component';
import { BarComponent }      from './bar.component';

@Component({
  selector: 'my-app',
  providers: [CountService],
  template: `
    <div>
      <h2>{{ title }}</h2>
      <dl>
        <dt>Counter Value:</dt>
        <dd>{{ getCount() }}</dd>
      </dl>
      <app-foo></app-foo>
      <app-bar></app-bar>
    </div>
  `,
  styles: ['dt { font-weight: bold; }']
})

export class App {
  constructor(private countService: CountService) {
    this.title = "Service Example 1";
  }
  
  getCount() {
    return this.countService.get();
  }
}

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

import { Injectable } from '@angular/core';

@Injectable()
export class CountService {
 
 constructor() { }
 
  public count = 0;
 
  get() {
    return this.count;
  }
 
  increment() {
    this.count++;  
  }
  
  decrement() {
    this.count--;
  }
  
}

import { Component } from '@angular/core';

import { CountService }      from './count.service';

@Component({
  selector: 'app-foo',
  template: `
  <fieldset>
    <legend>Foo Component</legend>
    <button (click)="incCount()">Increment</button>
  </fieldset>
  `
})
export class FooComponent {

  constructor(private countService: CountService) { }
  
  incCount() {
    this.countService.increment();
  }

}

import { Component } from '@angular/core';

import { CountService }      from './count.service';

@Component({
  selector: 'app-bar',
  template: `
  <fieldset>
    <legend>Bar Component</legend>
    <button (click)="decCount()">Decrement</button>
  </fieldset>
  `
})
export class BarComponent {

  constructor(private countService: CountService) { }

  decCount() {
    this.countService.decrement();
  }

}