Function expandSitemap

api/sitemap.js:50–73

(parsed, depth)

// Recursively flatten a sitemap-index into its child url sets
const expandSitemap = async (parsed, depth) => {
  if (!parsed?.sitemapindex?.sitemap || depth >= MAX_DEPTH) return parsed;
  const children = parsed.sitemapindex.sitemap
    .map((s) => s?.loc?.[0])
    .filter(Boolean)
    .slice(0, MAX_CHILD_SITEMAPS);
  const fetched = await Promise.all(
    children.map((loc) =>
      fetchSitemap(loc).catch((error) => {
        log.debug(`child sitemap failed for ${loc}`, error.message);
        return null;
      }),
    ),
  );
  const expanded = await Promise.all(
    fetched.map((child) => (child ? expandSitemap(child, depth + 1) : null)),
  );
  const urls = expanded.flatMap((child) => child?.urlset?.url || []);
  return {
    sitemapindex: parsed.sitemapindex,
    urlset: urls.length ? { url: urls } : undefined,
    sources: children,
  };
};

// Whether the parsed XML matched one of the canonical sitemap shapes
const isValidSitemap = (p) => !!(p?.urlset?.url?.length || p?.sitemapindex?.sitemap?.length);