coincident = (a,b) => {
if (!turf.booleanOverlap(a,b)) return false;
const dissolved = turf.dissolve(turf.featureCollection([a,b]));
dissolved.features[0].geometry = turf.cleanCoords(dissolved.features[0].geometry)
return ( turf.booleanWithin(a,b) && turf.lineIntersect(a,b).features.length > 0 && turf.area(dissolved.features[0]) === turf.area(b)) ? true : false;
}