Object that defineds node badge If the badge property is defined, then item count a badge will be display on the right of the item. The badge property has the following structure: { text : '' // string or function, html of the badge tooltip : '', // string or function, tooltip for the badge style : '', // style for the badge onClick : function // on click event badger } You can define nodes during object creation: let sidebar = new w2sidebar({ name : 'sidebar', img : 'icon-page', badge: { text(node) { return node.id }, style: 'height: 22px; width: 20px; margin-top: 0px; margin-left: -15px;', onClick(node) { console.log('Badge clicked', event.detail) } }, nodes: [ { id: 'id-1', text: 'Level 1' }, { id: 'id-2', text: 'Level 2' }, { id: 'id-3', text: 'Level 3' } ] }) or after the object has been created: w2ui.sidebar.badge = { text(node) { return node.id }, style: 'height: 22px; width: 20px; margin-top: 0px; margin-left: -15px;', onClick(node) { console.log('Badge clicked', event.detail) } } w2ui.sidebar.refresh()