Angular + Typescript Demo Plunk

<!DOCTYPE html>
<html>

  <head>
    <base href="." />
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" integrity="sha384-rwoIResjU2yc3z8GV/NPeZWAv56rSmLldC3R/AZzGRnGxQQKnKkoFVhFQhNUwEyJ" crossorigin="anonymous">
    <script src="https://code.jquery.com/jquery-3.1.1.slim.min.js" integrity="sha384-A7FZj7v+d/sdmMqp/nOQwliLvUsJfDHW+k9Omg/a/EheAdgtzNs3hpfag6Ed950n" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/tether/1.4.0/js/tether.min.js" integrity="sha384-DztdAPBWPRXSA/3eYEEUWrWCy7G5KFbe8fFjk5JAIxUYHKkDx6Qin1DkWx51bBrb" crossorigin="anonymous"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/js/bootstrap.min.js" integrity="sha384-vBWWzlZJ8ea9aCX4pEW3rVHjgjt7zpkNpZk+02D9phzyeVkE+jo0ieGizqPLForn" crossorigin="anonymous"></script>
    <script type="text/javascript" charset="utf-8">
      window.AngularVersionForThisPlunker = 'latest'
    </script>
    <title>angular 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></my-app>
  </body>

</html>

/* Styles go here */

### Angular Starter Plunker - Typescript

var angularVersion;
if(window.AngularVersionForThisPlunker === 'latest'){
  angularVersion = ''; //picks up latest
}
else {
  angularVersion = '@' + window.AngularVersionForThisPlunker;
}

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'+ angularVersion + '/bundles/core.umd.js',
    '@angular/common': 'npm:@angular/common' + angularVersion + '/bundles/common.umd.js',
    '@angular/compiler': 'npm:@angular/compiler' + angularVersion  + '/bundles/compiler.umd.js',
    '@angular/platform-browser': 'npm:@angular/platform-browser' + angularVersion + '/bundles/platform-browser.umd.js',
    '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic' + angularVersion + '/bundles/platform-browser-dynamic.umd.js',
    '@angular/http': 'npm:@angular/http' + angularVersion + '/bundles/http.umd.js',
    '@angular/router': 'npm:@angular/router' + angularVersion +'/bundles/router.umd.js',
    '@angular/forms': 'npm:@angular/forms' + angularVersion + '/bundles/forms.umd.js',
    '@angular/animations': 'npm:@angular/animations' + angularVersion + '/bundles/animations.umd.js',
    '@angular/platform-browser/animations': 'npm:@angular/platform-browser' + angularVersion + '/bundles/platform-browser-animations.umd.js',
    '@angular/animations/browser': 'npm:@angular/animations' + angularVersion + '/bundles/animations-browser.umd.js',
    
    '@angular/core/testing': 'npm:@angular/core' + angularVersion + '/bundles/core-testing.umd.js',
    '@angular/common/testing': 'npm:@angular/common' + angularVersion + '/bundles/common-testing.umd.js',
    '@angular/compiler/testing': 'npm:@angular/compiler' + angularVersion + '/bundles/compiler-testing.umd.js',
    '@angular/platform-browser/testing': 'npm:@angular/platform-browser' + angularVersion + '/bundles/platform-browser-testing.umd.js',
    '@angular/platform-browser-dynamic/testing': 'npm:@angular/platform-browser-dynamic' + angularVersion + '/bundles/platform-browser-dynamic-testing.umd.js',
    '@angular/http/testing': 'npm:@angular/http' + angularVersion + '/bundles/http-testing.umd.js',
    '@angular/router/testing': 'npm:@angular/router' + angularVersion + '/bundles/router-testing.umd.js',
    'tslib': 'npm:tslib@1.6.1',
    'rxjs': 'npm:rxjs',
    'typescript': 'npm:typescript@2.2.1/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, VERSION} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'

@Component({
  selector: 'my-app',
  template: `
    <div class="btn-group btn-group-sm" data-toggle="buttons">
  <label class="btn btn-primary" *ngFor="let item of list;let i=index">
    <input type="radio" name="domain" [value]="item" (click)="onSelectItem(i)"> {{item}}
  </label>
</div>
  `,
})
export class App {
  
  checked:number;
  constructor() { }
  list:string[]=["1","2","3"];

  ngOnInit() {
  }

  isChecked(i:number){
    console.log("i:",i,"checked:",this.checked);
    if(i==this.checked){
      console.log("this shit is supposed to be checked");
      return true;
    }
    return false;
  }

  onSelectItem(i:number){
    this.checked=i;
    console.log(i);
  }
}

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