in lib/h3core.js [317:331]
function polygonArrayToGeoLoop(polygonArray, geoLoop, isGeoJson) {
const numVerts = polygonArray.length;
const geoCoordArray = C._calloc(numVerts, SZ_LATLNG);
// Support [lng, lat] pairs if GeoJSON is specified
const latIndex = isGeoJson ? 1 : 0;
const lngIndex = isGeoJson ? 0 : 1;
for (let i = 0; i < numVerts * 2; i += 2) {
C.HEAPF64.set(
[polygonArray[i / 2][latIndex], polygonArray[i / 2][lngIndex]].map(degsToRads),
geoCoordArray / SZ_DBL + i
);
}
C.HEAPU32.set([numVerts, geoCoordArray], geoLoop / SZ_INT);
return geoLoop;
}