This is the code
this.events.push(
gantt.attachEvent('onMouseMove', (event_id, ev) => {
let linkageDetails;
let linkId;
// @ TODO, un commented the due to resolve the build issue
//linkId = gantt.locate(ev, 'link_id');
linkId = gantt.locate(ev);
console.log('LINK ID', gantt.getLink('link_id'));
if (linkId) {
linkageDetails = ganttChartService.constructLinkageDetailsMarkUp(linkId);
gantt._show_tooltip(linkageDetails, gantt._tooltip_pos(ev));
}
})
);