title: How to properly pass $index in bootstrap data target v-for?
body: <p>i created dynamic ids using v-for index,
  the problem is when i'm trying to use bootstrap's
  data-target to link the div</p>
  
  <p><strong>THIS don't work</strong></p>
  
  <pre><code>&lt;button data-toggle="collapse" data-target="'#demo'+{{$index}}"&gt;EXPAND&lt;/button&gt; 
  
              &lt;br/&gt;
              &lt;div v-bind:id="['demo'+index]" class="collapse"&gt;
                  {{service.sotto[index]}}
              &lt;/div&gt;
  </code></pre>
  
  <p>so how to properly use data-target + index ?</p>