Как динамически изменять отображение / скрытие div с помощью значков fa fa-minus и fa fa-plus в angular 2

Есть очень простой способ сделать это очень просто. Я использую массив Boolean, чтобы получить этот результат

шаблон:

  <div class = "box box-info" *ngFor = "let item of result; let x = index"> <!-- make loop for draw forms -->
    <div class = "box-header with-border">
      <h3 class = "box-title"><span *ngIf = "item.hasChildren" class = "fa fa-sign-out"></span> {{item.name}}</h3>

      <div class = "box-tools pull-right">
        <a class = "btn btn-box-tool" data-widget = "collapse" (click) = "toggle(x)">
          <!-- use colapse[x] to change minus to plus -->
          <i class = "fa" [ngClass] = "{'fa-minus': colapse[x], 'fa-plus': !colapse[x]  }"></i>
        </a>
      </div>
    </div>
    <!-- show/hide div -->
    <div class = "box-body" *ngIf = "colapse[x]">
      <div class = "table-responsive">
        <table class = "table no-margin">
          <thead>
            <tr>
              <th>numbering</th>
              <th>description</th>
              <th>value</th>
            </tr>
          </thead>
          <tbody>
            <tr *ngFor = "let setting of item.configs; let i = index" >
              <td>{{i + 1}}</td>
              <td>{{setting.description}}</td>
              <td class = "col-lg-3 col-md-4">
                <input type = "text" class = "form-control" [(ngModel)] = "setting.value" name = "value" #ngvalue = "ngModel"  value = "{{setting.description}}">
              </td>
            </tr>
          </tbody>
        </table>
      </div>
    </div>
  </div>

вот OnInit файла .ts:

export class MyComponent implements OnInit {

  //for result from service
  result: ConfigGroups[];
  //for show/hide box
  colapse: boolean[] = [false];

  constructor(private settingService: SettingService) { }

  ngOnInit() {
    this.settingService.getConfigGroup(null, null).subscribe(res => {
      //map return object to class
      this.result = <ConfigGroups[]>res.data.configGroups;

    }, error => { }, () => { });

  }

  // show/hide box and change fa icons
  toggle(id) {

    if (!this.colapse[id]) {
      this.colapse[id] = true;
    }
    else {
      this.colapse[id] = !this.colapse[id];
    }
  }
}