onCurrentIndexChanged not firing

I’ve found a way to make this work. It would make more sense for onCurrentIndexChanged to either return a promise or to have an onPageLoaded function, however, I’ve combined the two to get at least my own desired results.

function formatItems () {
    $w('#itemRepeater').forEachItem(($item, itemData, index) => {
        // Change whatever needs to be changed after new items loaded
    }
}

$w.onReady(function () {
    $w('#mediaDataset').onReady(formatItems);
    $w('#mediaDataset').onCurrentIndexChanged((index) => {
        $w('#mediaDataset').loadPage($w('#mediaDataset').getCurrentPageIndex())
            .then(formatItems);
    });
});