lib/bootstrap-v4/app/components/bootstrap/bs-dropdown-button.js
import ButtonComponent from 'client/components/bootstrap/bs-button';
export default ButtonComponent.extend({
attributeBindings: ['aria-haspopup', 'aria-expanded', 'data-toggle'],
classNames: ['dropdown-toggle'],
'aria-haspopup': 'true',
'aria-expanded': 'false',
'data-toggle': 'dropdown'
});