Closetlayer function not working with GeoJson

[ayushjoshi1]

I am trying to use the closetlayer function to find the closest point on a geoJson file but keep getting a "Cannot read properties of null (reading 'lat')" error. May geojson file is a linestring. Any ideas on what I may be doing wrong?

var geojsonLayer = new L.GeoJSON.AJAX("XXX.geojson", {
    style: {color: 'red', 
            weight: 4}
});       
geojsonLayer.addTo(map);
const coordinates_array = geojsonLayer.getLayers().map(l => l.feature.geometry.coordinates)

markerClosestPolyline1 = null

map.on('click', function(e) {
  
  const coordinates_array = geojsonLayer.getLayers().map(l => l.feature.geometry.coordinates)
  let closest_latlng = L.GeometryUtil.closestLayer(map, coordinates_array, e.latlng)

  markerClosestPolyline1 = L.marker(closest_latlng).addTo(map).bindPopup('Closest point on polyline1');
})

The error is pointing me to this portion of the code (Im guessing its an error related to the way im loading my geojson file)

	project: function (latlng) {
		var d = Math.PI / 180,
		    max = this.MAX_LATITUDE,
		    lat = Math.max(Math.min(max, latlng.lat), -max),
		    sin = Math.sin(lat * d);