title: angular2 - Forms - Cannot set property 'stack' of undefined
body: <p>When Creating my first form in Angular2, I get this following Error:</p>
  
  <blockquote>
    <p>Unhandled Promise rejection: Cannot set property 'stack' of undefined
    ; Zone:  ; Task: Promise.then ; Value: TypeError: Cannot set
    property 'stack' of undefined</p>
  </blockquote>
  
  <p>I am using anguilar-cli 1.0.0-beta.25.5.
  **
  here is my code:</p>
  
  <pre><code>import { Component } from '@angular/core';
  import {FormControl, FormGroup} from '@angular/forms';
  
  @Component({
    selector: 'app-root',
    template:
      `&lt;div class="container"&gt;
             &lt;form [formGroup]="userForm" (ngSubmit)="submitHandler()"&gt;
               &lt;div class="form-group"&gt;
                  &lt;input type="text" class="form-control"       formControlName="username"
    placeholder="username..."&gt;
              &lt;/div&gt;
            &lt;/form&gt;
       &lt;/div&gt;`
  })
  export class AppComponent {
    private userForm : FormGroup;
  
    constructor(){
      this.userForm = new FormGroup({
        username : new FormControl(),
        password : new FormControl(),
        email : new FormControl(),
      });
  
    }
  }
  </code></pre>