Angular2: Property 'controls' does not exist on type 'AbstractControl'. Error when accessing .control of an object within a formarray thru an index : <p>I'm trying to push another formbuilder within a formarray but it gives me an error since I think there are no items in the array when initializing the code, hence there are no controls. The error is Property 'controls' does not exist on type 'AbstractControl' after the</p>

<pre><code>(&lt;FormArray&gt;this.loanTypeForm.controls['frequency']).controls[index]
</code></pre>

<p>I'm using angular 2.0.0-beta.17</p>

<pre><code>let settingsForm: FormArray = new FormArray([]);
      (&lt;FormArray&gt;this.loanTypeForm.controls['frequency']).push(
        this.formBuilder.group({
          'name': [value, Validators.required],
          'settings': settingsForm,
        })
      );
(&lt;FormArray&gt;this.loanTypeForm.controls['frequency']).controls[index].controls['settings'].push(
      this.formBuilder.group({
        'term': [null, Validators.required],
        'eir': [null, Validators.required],
      })
    );
</code></pre>
