app/views/media_resources/actions/_favor_toggle.html.haml
:ruby
is_favorite = current_user.favorite_ids.include?(media_resource.id)
%a.button{:"data-favor-toggle" => true,
:"data-is-fav" => is_favorite ? "true" : "false",
:title => _("Add to/remove from favorites")}
%i.icon-star-empty.ui-thumbnail-action-favorite{class: is_favorite ? "active" : ""}