Returning polygon attributes intersecting a buffer

Question

I am trying to return attributes of polygons (from the SAC feature) that intersect the buffer created around the route, but I keep getting:

Uncaught Error: geojson must be a valid Feature or Geometry

Here is my code:

/*OVERLAYS*/
var SAC = L.geoJson({{ sac }} , {
 style: function(feature) {
return {
 color: "black",
 fill:'url(img/image.gif)',
 weight: 1,
 opacity: 0.8
};
},
onEachFeature: function(feature, layer) {
 const p = feature.properties
p.title = p.SAC_NAME || p.name 
layer.on('mouseover', function() {
 this.setStyle({
 'fillColor': '#0000ff'
 });
});
layer.on('mouseout', function() {
 this.setStyle({
 'fillColor': 'transparent'
 });
});
//mouse tooltip properties
if (p && p.name) {
 layer.bindTooltip(p.name, {
 closeButton: false,
 offset: L.point(0, -20)
 });
 layer.on('mouseover', function() {
 layer.openPopup();
 });
 layer.on('mouseout', function() {
 layer.closePopup();
 });
 }
 }
 })

Add buffer layer around route:

document.getElementById('radius').onchange = function() {
 var radius = parseInt(document.getElementById('radius').value);
 // if (isNaN(radius)) radius = 500;
 var buffered = turf.buffer(PreferredTerrestrialRoute.toGeoJSON(), radius , {units: 'kilometres'});
 map.removeLayer(roadbuf);/* remove existing laer*/
roadbuf = new L.GeoJSON(buffered, {
style: function(feature) {
return {
 color: "green",
 fill:"green",
 weight: 1,
 // fillColor: "transparent",
 // color: "blue",
 opacity: 0.8
};
 },
})
map.addLayer(roadbuf) 
var polyintersect = turf.intersect(SAC.toGeoJSON(), roadbuf.toGeoJSON());
 console.log( polyintersect.features.length +" points in this poly");
 alert("results "+JSON.stringify(ptsWithin4));
}

• TomazicM: There is a lot of code. At which line you are getting the error?
• lloyd: @TomazicM this line var polyintersect = turf.intersect(SAC.toGeoJSON(), roadbuf.toGeoJSON()); console.log( polyintersect.features.length +" points in this poly"); alert("results "+JSON.stringify(ptsWithin4))
• Babel: Are you trying to do something similar to this and could that help? gis.stackexchange.com/a/388414/88814
• TomazicM: turf.intersect expects two GeoJSON polygons, so there is something wrong with either SAC.toGeoJSON() or roadbuf.toGeoJSON(). Examine contents of those two.