bugfix: menuGroup build unique key

components/MenuButtonGroup.js

@@ -20,7 +20,7 @@ const MenuButtonGroup = ({ allowCollapse = false }) => {
       {links.map(link => {
         if (link.show) {
           const selected = (router.pathname === link.to) || (router.asPath === link.to)
-          return <Link key={link.id + link.icon} title={link.to} href={link.to} >
+          return <Link key={`${link.id}-${link.to}`} title={link.to} href={link.to} >
             <a className={'py-1 my-1 px-5 mx-2 duration-300 text-base hover:bg-gray-500 hover:text-white hover:shadow-lg cursor-pointer font-light flex flex-nowrap items-center ' +
               (selected ? 'bg-gray-700 text-white ' : ' ')} >
               <div className='my-auto justify-center flex '>
@@ -30,7 +30,7 @@ const MenuButtonGroup = ({ allowCollapse = false }) => {
             </a>
           </Link>
         } else {
-          return <></>
+          return null
         }
       })}
     </nav>