Function on

modular/sortable.core.esm.js:131–133

(el, event, fn)

  passive: false
};
function on(el, event, fn) {
  el.addEventListener(event, fn, !IE11OrLess && captureMode);
}
function off(el, event, fn) {
  el.removeEventListener(event, fn, !IE11OrLess && captureMode);
}