in src/geojson2h3.js [151:163]
function h3ToFeature(h3Index, properties = {}) {
// Wrap in an array for a single-loop polygon
const coordinates = [h3.h3ToGeoBoundary(h3Index, true)];
return {
type: FEATURE,
id: h3Index,
properties,
geometry: {
type: POLYGON,
coordinates
}
};
}