Display .kml file in Leaflet

I would like to show my .kml file in my leaflet map.~

There is a plugin:
https://github.com/windycom/leaflet-kml
whixh unfortunately doesn’t work. It show only a blank map in the coordinates provided.
This issue has been risen here:
https://github.com/windycom/leaflet-kml/issues/3
where the basic explanation refers to the:

.then( res => response.text() )

and

const track = new L.KML(kml)

provided in the example:

https://github.com/genomexyz/sigmet-map

I have already uploaded my L.KML.js file alongside with the code, which now looks like this:

 // Load kml file
        fetch('LotA.kml')
            .then(res => response.text())
            .then(kmltext => {
                // Create new kml overlay
                const parser = new DOMParser();
                const kml = parser.parseFromString(kmltext, 'text/xml');
                const track = new L.KML(kmltext, 'text/xml');
                map.addLayer(track);

                // Adjust map to show the kml
                const bounds = track.getBounds();
                map.fitBounds(bounds);
            });

But the blank map comes again. I believe, that the change is minor, although I don’t know certainly where.
Is anyone able to clarify?

// Load kml file
fetch('LotA.kml')
  .then(res => response.text())
  .then(kmltext => {
    // Create new kml overlay
    const parser = new DOMParser();
    const kml = parser.parseFromString(kmltext, 'text/xml');
    const track = new L.KML(kmltext, 'text/xml');
    map.addLayer(track);

    // Adjust map to show the kml
    const bounds = track.getBounds();
    map.fitBounds(bounds);
}).catch((e) => {
  console.log(e);
});