Angular2 + select 1st radiobutton

<!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 */

### 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'

@Component({
  selector: 'my-app',
  template: `
    <div>
      <h2>Binding radio buttons</h2>
      
      <p>Binding radio button lists</p>
      
      <table>
        <thead>
          <td>Description</td>
          <td></td>
        </thead>
        <tbody>
          <tr *ngFor="let entry of entries; let idx = index">
            <td>{{ entry.description }}</td>
            <td><input type="radio" name="radiogroup" (change)="onSelectionChange(entry)" [checked]="(idx === 0)" [value]="entry.id"></td>
          </tr>
        </tbody>
      </table>
      
      <hr>
      
<pre>
{{ this.selectedEntry | json }}
</pre>
      
    </div>
  `,
})
export class App {
  entries = [];
  selectedEntry: { [key: string]: any } = {
    value: null,
    description: null
  };
  
  constructor() {
  }
  
  ngOnInit() {
    this.entries = [
      {
        description: 'entry 1',
        id: 1
      },
      {
        description: 'entry 2',
        id: 2
      },
      {
        description: 'entry 3',
        id: 3
      },
      {
        description: 'entry 4',
        id: 4
      }
    ];
    
    // select the first one
    if(this.entries) {
      this.onSelectionChange(this.entries[0]);  
    }
    
  }
  
  onSelectionChange(entry) {
    // clone the object for immutability
    this.selectedEntry = Object.assign({}, this.selectedEntry, entry);
  }
  
}

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