app/views/spree/favorite_products/create.js.erb
<% if @success %>
$('.favorite_link').attr('href', '<%= favorite_product_path(id: params[:id], type: params[:type]) %>').attr('id', 'unmark_as_favorite').data('method', 'delete').text('<%= Spree.t(:unmark_as_favorite) %>')
var $item = $("#favorite_variant_<%= params[:id]%>"),
$removeFromCart = $item.closest('tr').find('a.delete');
$item.remove();
$removeFromCart.click(); // remove it from cart
<% end %>
alert("<%=j @message%>");