Conditional attribute inside a repeat

Hi I am trying to figure out how to add an area-expanded="true" only for the first result. Using the $index==0 just cant figure oiut how to code this properly Below is my example

  <li role="presentation" dmx-class:active="$index == 0" dmx-bind:area-expanded="true" >
			    <a dmx-bind:href="#tab{{album_id}}"  dmx-bind:aria-controls="#tab{{album_id}}" role="tab" data-toggle="tab">{{album_name_gr}}</a>
			  </li>

As you see I have used the $index==0 to add the active class in the first result only. I want to do the same for the dmx-bind:area-expanded="true'

Currently the code as is, it adds the area-expanded=“true” to every repeated element which is something I want to avoid.

Thank you in advance.