in src/geojson2h3.js [190:205]
function h3SetToFeature(hexagons, properties = {}) {
const polygons = h3.cellsToMultiPolygon(hexagons, true);
// See if we can unwrap to a simple Polygon.
const isMultiPolygon = polygons.length > 1;
const type = isMultiPolygon ? MULTI_POLYGON : POLYGON;
// MultiPolygon, single polygon, or empty array for an empty hex set
const coordinates = isMultiPolygon ? polygons : polygons[0] || [];
return {
type: FEATURE,
properties,
geometry: {
type,
coordinates
}
};
}