tag first, then og:title, then <h1>\n let title = \"\";\n\n // Try Open Graph title (most reliable for article titles)\n const ogMatch = html.match(/<meta\\s+property=\"og:title\"\\s+content=\"([^\"]+)\"/i)\n || html.match(/<meta\\s+content=\"([^\"]+)\"\\s+property=\"og:title\"/i);\n if (ogMatch) {\n title = ogMatch[1].trim();\n }\n\n // Fallback: <title> tag (strip \" | National Geographic\" suffix)\n if (!title) {\n const titleMatch = html.match(/<title[^>]*>([^<]+)<\\/title>/i);\n if (titleMatch) {\n title = titleMatch[1]\n .replace(/\\s*[|\\-–—]\\s*(National Geographic.*)?$/i, \"\")\n .trim();\n }\n }\n\n // Fallback: first <h1>\n if (!title) {\n const h1Match = html.match(/<h1[^>]*>([^<]+)<\\/h1>/i);\n if (h1Match) {\n title = h1Match[1].trim();\n }\n }\n\n return { pubDate, title: title ? escapeXml(title) : \"\" };\n } catch {\n return { pubDate: \"\", title: \"\" };\n }\n}\n\n// Run `fn` over `items` with at most `concurrency` in-flight at once\nasync function mapWithConcurrency<T, U>(\n items: T[],\n concurrency: number,\n fn: (item: T) => Promise<U>,\n): Promise<U[]> {\n const results: U[] = new Array(items.length);\n let index = 0;\n\n async function worker() {\n while (index < items.length) {\n const i = index++;\n results[i] = await fn(items[i]);\n }\n }\n\n const workers = Array.from({ length: concurrency }, () => worker());\n await Promise.all(workers);\n return results;\n}\n\nfunction urlToTitle(url: string): string {\n const slug = url.split(\"/\").pop() || \"\";\n return slug\n .replace(/-/g, \" \")\n .replace(/\\b\\w/g, (c) => c.toUpperCase());\n}\n\nfunction capitalize(s: string): string {\n return s.charAt(0).toUpperCase() + s.slice(1);\n}\n\nfunction escapeXml(str: string): string {\n return str\n .replace(/&/g, \"&\")\n .replace(/</g, \"<\")\n .replace(/>/g, \">\")\n .replace(/\"/g, \""\")\n .replace(/'/g, \"'\");\n}\n\nfunction buildRSS(articles: Article[]): string {\n const now = new Date().toUTCString();\n\n const items = articles\n .map(\n (a) => `\n <item>\n <title>${a.title}

Diff · v8