title: How to disable all FormControls inside a FormGroup
body: <p>I have this reactive Angular Form structure:</p>
  
  <pre class="lang-js prettyprint-override"><code>myForm: FormGroup;
  Personal: FormGroup;
  FIRST_NAME: FormControl;
  LAST_NAME: FormControl;
  ngOnInit(): void {
      this.createFormControls();
      this.createForm();
  }
  createFormControls() {
      this.FIRST_NAME = new FormControl('', [Validators.required]);
      this.LAST_NAME = new FormControl('', [Validators.required]);
  }
  createForm(): void {
      this.myForm = this.fb.group({
          Personal: this.fb.group({
              FIRST_NAME: this.FIRST_NAME,
              LAST_NAME: this.LAST_NAME,
          })
      })
  }
  </code></pre>
  
  <p>If I do:</p>
  
  <pre class="lang-js prettyprint-override"><code>this.FIRST_NAME.disable();
  </code></pre>
  
  <p>it disables the FormControl.</p>
  
  <p>How to disable all FormControls in <code>Personal</code> FormGroup </p>