in lib/h3core.js [920:930]
export function childPosToCell(childPos, h3Index, childRes) {
const [cpLower, cpUpper] = numberToSplitLong(childPos);
const [lower, upper] = h3IndexToSplitLong(h3Index);
const child = C._malloc(SZ_H3INDEX);
try {
throwIfError(H3.childPosToCell(cpLower, cpUpper, lower, upper, childRes, child));
return validateH3Index(readH3IndexFromPointer(child));
} finally {
C._free(child);
}
}