Angular2 tabbed component using @ContentChildren

<!DOCTYPE html>
<html>

  <head>
    <base href="." />
    <title>angular2 tab implementation</title>
    <link data-require="bootstrap-css@*" data-semver="3.3.1" rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.1/css/bootstrap.min.css" />
    <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.1

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

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 {Tabs} from './tabs';
import {Tab} from './tab';

@Component({
  selector: 'my-app',
  template: `
    <tabs>
      <tab [tabTitle]="'Tab 1'">Tab 1 Content</tab>
      <tab tabTitle="Tab 2">Tab 2 Content</tab>
    </tabs>
  `
})
class App {
  constructor() {
    this.name = 'Angular2'
  }
}

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

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

@Component({
  selector: 'tab',
  styles: [`
    .pane{
      padding: 1em;
    }
  `],
  template: `
    <div [hidden]="!active" class="pane">
      <ng-content></ng-content>
    </div>
  `
})
export class Tab {
  @Input('tabTitle') title: string;
  @Input() active = false;
}

import { Component, ContentChildren, QueryList, AfterContentInit } from '@angular/core';
import { Tab } from './tab';

@Component({
  selector: 'tabs',
  template:`
    <ul class="nav nav-tabs">
      <li *ngFor="let tab of tabs" (click)="selectTab(tab)" [class.active]="tab.active">
        <a href="#">{{tab.title}}</a>
      </li>
    </ul>
    <ng-content></ng-content>
  `
})
export class Tabs implements AfterContentInit {
  
  @ContentChildren(Tab) tabs: QueryList<Tab>;
  
  // contentChildren are set
  ngAfterContentInit() {
    // get all active tabs
    let activeTabs = this.tabs.filter((tab)=>tab.active);
    
    // if there is no active tab set, activate the first
    if(activeTabs.length === 0) {
      this.selectTab(this.tabs.first);
    }
  }
  
  selectTab(tab: Tab){
    // deactivate all tabs
    this.tabs.toArray().forEach(tab => tab.active = false);
    
    // activate the tab the user has clicked on.
    tab.active = true;
  }

}