I have the following html:
  <li ng-repeat="document in collection">
        <span ng-repeat="(key, value) in document.nestedDocument">
            <input type="text" ng-model="document.nestedDocument[key]"> 
        </span>
      <quick-datepicker ng-model="myDate"></quick-datepicker>
      <button ng-click="dateFunction($index)" class="btn btn-info">SetDate</button>
  </li>
Now how can I apply CSS to <quick-datepicker ng-model="myDate"> of only the index clicked?
e.g. I could run in the controller:
   $scope.isActive = true;
and add to my 'quick-datepicker' html:
ng-class="{true: 'active', false:'inactive'}[isActive]"
and have some CSS classes:
.active {
    color: red;
}
.inactive {
    color: black;
}
But this would color all datepicker elements inside ng-repeat. How to apply only to the one whose $index is clicked (meaning the index inside the "document in collection ng-repeat")?
Screenshot:

