How to add ToolTip to DropDownButton items

<button ejs-dropdownbutton [items]='items' content="Profile" (beforeItemRender)="itemRender($event)" (beforeClose)="OnBeforeClose($event)"></button>

import {ItemModel, MenuEventArgs, BeforeOpenCloseMenuEventArgs} from '@syncfusion/ej2-angular-splitbuttons'; 
import {Tooltip, TooltipEventArgs} from '@syncfusion/ej2-popups'; 
 
export class AppComponent implements OnDestroy { 
    
    public tooltip: Tooltip; 
 
    //DropDownButton items definition 
    public items: ItemModel[] = [ 
        //.. 
    ]; 
 
    ngAfterViewInit() { 
        //Initialize Tooltip component 
        this.tooltip = new Tooltip({ 
            // default content of tooltip 
            content: 'Loading...', 
            // set target element to tooltip 
            target: '.e-custom-tooltip', 
            // bind beforeRender event 
            beforeRender: this.onBeforeRender 
        }); 
        this.tooltip.appendTo('body'); 
    } 
 
    //beforeRender event of tooltip 
    onBeforeRender(args: TooltipEventArgs): void { 
        (this as any).content = args.target.textContent; 
    } 
 
    //To add tooltip for DropDownButton item 
    public itemRender(args: MenuEventArgs) { 
        args.element.classList.add("e-custom-tooltip"); 
    } 
 
    //To close tooltip while closing DropDownButton Item 
    OnBeforeClose(args: BeforeOpenCloseMenuEventArgs) { 
        this.tooltip.close(); 
    } 
    
    //To destroy the tooltip
    ngOnDestroy() { 
        this.tooltip.destroy(); 
    } 
}