addon/components/folding-panel/component.js
import { alias } from '@ember/object/computed';
import Component from '@ember/component';
import { inject as service } from '@ember/service';
import layout from './template';
import LayoutClasses from '../../mixins/layout-classes';
export default Component.extend(LayoutClasses, {
panel: service(),
layout,
classNames: ['folding-panel'],
classNameBindings: ['panel.foldIsOpen:is-open'],
selected: alias('panel.selected')
});