public/components/compactor-toggle/compactor-toggle.html

<button class="compactor-toggle" ng-click="compactView.visible = !compactView.visible" title="Toggle compact view">
  Toggle compact view
  <div
    class="compactor-toggle__compactor-icon"
    ng-class="{'compactor-toggle__compactor-icon--active': compactView.visible }"
  ></div>
</button>