title: How to trigger bootstrap collapse in Angular 2/Typescript
body: <p>Let's say I've this <strong>panel</strong>. I want to be able to expend/collapse it, depending on the selected value of a dropdownlist.</p>
  
  <pre><code>&lt;div class="collapse" id="collapseExample"&gt;
      &lt;div class="well"&gt;
          ...
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>This is the <strong>dropdownlist</strong>.</p>
  
  <pre><code>&lt;select id="state" name="state"
          [(ngModel)]="stateId"    
          (change)="onChange($event.target.id, $event.target.value)"
          class="form-control"&gt;
          &lt;option *ngFor="let r of statesList"
              value="{{ r.id }}"&gt;{{ r.name }}
          &lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>This is the <strong>event handler</strong>. And, if a state is selected, expends the panel. Otherwise, collapse the panel.</p>
  
  <pre><code>//Events
  onChange(id: string, deviceValue: string) {
       if (id == "state") {
          if (deviceValue) {
              //expend the panel...
          }
          else{
              //collapse the panel...
          }
       }
  }
  </code></pre>
  
  <p>using <strong>Jquery</strong>, I could just do something like: <code>$("#collapseExample").collapse();</code>.</p>
  
  <p>How to get the samething in <code>Angular/Typescript</code>?.</p>