class ActiveAdmin::HasManyBuilder

def js_for_has_many(class_string, &form_block)

Capture the ADD JS
def js_for_has_many(class_string, &form_block)
  assoc_name = assoc_klass.model_name
  placeholder = "NEW_#{assoc_name.to_s.underscore.upcase.gsub(/\//, '_')}_RECORD"
  opts = {
    for: [assoc, assoc_klass.new],
    class: class_string,
    for_options: { child_index: placeholder }
  }
  html = template.capture { __getobj__.send(:inputs_for_nested_attributes, opts, &form_block) }
  text = new_record.is_a?(String) ? new_record : I18n.t("active_admin.has_many_new", model: assoc_name.human)
  template.link_to text, "#", class: "button has_many_add", data: {
    html: CGI.escapeHTML(html).html_safe, placeholder: placeholder
  }
end