if array is empty in a repeater (wix Stores)?

Try this one, perhaps it works…

$w.onReady(function () {
    $w("#repeater1").onItemReady(($item, itemData, index) => {
 let ribbonText = itemData.ribbons[0].text;
 let array = itemData.ribbons;
 if (ribbonText === undefined){
        $item('#ribbon').hide();
    }
 else {
       $item('#ribbon').show();
       $item('#ribbon').label = ribbonText;
   }
});

});