Angular2 collapsible

<!DOCTYPE html>
<html>

  <head>
    <title>angular2 playground</title>
    <link data-require="bootstrap-css@3.3.6" data-semver="3.3.6" rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.css" />
    <link rel="stylesheet" href="style.css" />
    <script src="https://code.angularjs.org/2.0.0-beta.0/angular2-polyfills.js"></script>
    <script src="https://code.angularjs.org/tools/system.js"></script>
    <script src="https://code.angularjs.org/tools/typescript.js"></script>
    <script src="config.js"></script>
    <script src="https://code.angularjs.org/2.0.0-beta.0/Rx.js"></script>
    <script src="https://code.angularjs.org/2.0.0-beta.0/angular2.min.js"></script>
    <script src="https://code.angularjs.org/2.0.0-beta.0/http.min.js"></script>
    <script>
    System.import('app')
      .catch(console.error.bind(console));
  </script>
  </head>

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

</html>

/* Styles go here */

.someclass{
  color:red;
}

### Angular2 Starter Plunker - Typescript - Beta 0

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
  },
  //map tells the System loader where to look for things
  map: {
    app: "./src"
  },
  //packages defines our app package
  packages: {
    app: {
      main: './main.ts',
      defaultExtension: 'ts'
    }
  }
});

//main entry point
import {bootstrap} from 'angular2/platform/browser';
import {App} from './app';

bootstrap(App, [])
  .catch(err => console.error(err));

//our root app component
import {Component} from 'angular2/core'
import {Collapse} from 'src/collapse'
@Component({
  selector: 'my-app',
  providers: [],
  template: `
    <div>
      <h2 (click)="isCollapsed = !isCollapsed">click here</h2>
      
      <div  [collapse]="isCollapsed" >
        <div class="well">
          panel panel panel
        </div>
      </div>
      
    </div>
  `,
  directives: [Collapse]
})
export class App {
  constructor() {
    this.name = 'Angular2'
  }
}

import {Directive, Input, HostBinding, ElementRef} from 'angular2/core'
@Directive({selector: '[collapse]'})
export class Collapse { 

  @HostBinding('class.collapsing') 
  private isCollapsing:boolean   

    // style
  @HostBinding('style.height') 
  private height:string;
  
  
  @Input()
  private set collapse(value:boolean) { 
    if(value!==undefined){
      if(value){ 
        this.hide(); 
      }else { 
        this.show();
      }
    }
    //
  }
  constructor(public el: ElementRef) {
    
    this.measureHeight(); 
  }  
  measureHeight() {
    let elem = this.el.nativeElement;
    //lets be sure the element has display:block style
    elem.className = elem.className.replace('collapse', '');
    this.h = elem.scrollHeight;
   
  }
  hide(){
    this.height = this.h +'px'
    setTimeout(() => {
        this.height = '0px';
        this.isCollapsing = true;//apply 'collapsing' class
    },1); 
  }
  show() {
    this.height = '0px'
    setTimeout(() => {
        this.height = this.h + 'px';
        this.isCollapsing = true;//apply 'collapsing' class
    },1);
  }
  
}