Var go into while() then out can not use

Desktop
1 
let menuItem = new PopupMenu.PopupSubMenuMenuItem('Fav', true, {});
...
while(...) {
    menuItem = new PopupMenu.PopupSubMenuMenuItem('aaa', true, {});
    ...
}
...
menuItem = new PopupMenu.PopupImageMenuItem('Set', 'settings', {}); // Can not use, no error
...