mapbox omnivore cannot parse kml string - laravel-8

Question

Currently, i've getting the string data from the maps.kml to display in laravel blade for simple testing. Based on the official documentation, mapbox can parse the kml string to maps. But it wont displayed.
Controller
...
$excelFile = public_path().'/assets/excel.xlsx';
$kmlfile = public_path(). '/assets/maps.kml';
$kmlContent = file_get_contents($kmlfile);
$kmlLoad = simplexml_load_string($kmlContent);
$kmlJsonFile = $kmlLoad->Document->Folder->Placemark;
// $kmlJson = json_decode($kmlLoad);
$parse = SimpleXLSX::parse($excelFile);
if ($parse) {
$petaSheet = $parse->rows(0, 0); //worksheet index, row limit
foreach($kmlJsonFile as $item)
{
foreach($petaSheet as $peta)
{
if($peta[0] == $item->name)
{
$item->Style->LineStyle->color = $peta[0];
}
}
}
// $monitorSheet = $parse->rows(1, 0);
} else {
$excelRaw = SimpleXLSX::parseError();
}
// $kmlJsonFile = json_encode($kmlJsonFile);
return view('home', [
'peta' => $petaSheet,
'kml' => $kmlContent
]);
Here the js file inside laravel blade
var kmlString = "";
kmlString += `{!! $kml !!}`;
var runLayer = omnivore.kml.parse(kmlString)
.on('ready', function() {
map.fitBounds(runLayer.getBounds());
})
.addTo(map);