title: Angular: Define default value input FormField in a FormGroup
body: <p>As can be seen in the code below, I'm setting the default value to an text-area:</p>
  
  <pre><code>&lt;form [formGroup]="entryForm" (ngSubmit)="onSubmit()"&gt;
       &lt;div class="view"&gt;
              &lt;div class="col"&gt;
                          &lt;mat-form-field&gt;
                              &lt;textarea matInput value="Test..." formControlName="firstValue"&gt;&lt;/textarea&gt;
                          &lt;/mat-form-field&gt;
              &lt;/div&gt;
              &lt;button type="submit"&gt;Submit&lt;/button&gt;
        &lt;/div&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>And i'm initialize my FormGroup and FormFields like this:</p>
  
  <pre><code>ngOnInit() {
   this.entryForm = new FormGroup({
     firstValue: new FormControl('')
   });
  }
  
  public onSubmit() {
    console.log(this.entryForm.value);
  }
  </code></pre>
  
  <p>But when I click on submit, the value of <code>firstValue</code> appears to be empty and not with the "Test..." value, like is been defined in the dom element.</p>