function generateSiteMap(data) {
  const xmlUrls = data.map((item) => {
      return `
      <url>
        <loc>${item.path}</loc>
        <lastmod>${item.date}</lastmod>
        <changefreq>monthly</changefreq>
        <priority>1</priority>
      </url>
    `;
    })
    .join("");

  return `<?xml version="1.0" encoding="UTF-8"?>
   <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
     
     <url>
       <loc>https://www.softwarestudiopro.com</loc>
       <lastmod>2024-01-20</lastmod>
       <changefreq>monthly</changefreq>
       <priority>1</priority>
     </url>
     <url>
       <loc>https://www.softwarestudiopro.com/contact-us</loc>
       <lastmod>2024-01-20</lastmod>
       <changefreq>monthly</changefreq>
       <priority>1</priority>
     </url>
      ${xmlUrls}
   </urlset>
 `;
}

function SiteMap() {
  // getServerSideProps will do the heavy lifting, no need to do anything here
}

export async function getServerSideProps({ res }) {
  // We make an API call / create a dataset to gather the URLs for our site
    const request = await fetch(EXTERNAL_DATA_URL);
    const data = await request.json();

  // We generate the XML sitemap with the data assuming we get an array as a response in data 
  const sitemap = generateSiteMap(data);
  res.setHeader("Content-Type", "text/xml");

  // we send the XML to the browser
  res.write(sitemap);
  res.end();

  return {
    props: {},
  };
}

export default SiteMap;

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://www.softwarestudiopro.com</loc>
    <lastmod>2024-01-20</lastmod>
    <changefreq>monthly</changefreq>
    <priority>1</priority>
  </url>
  <url>
    <loc>https://www.softwarestudiopro.com/contact-us</loc>
    <lastmod>2024-01-20</lastmod>
    <changefreq>monthly</changefreq>
    <priority>1</priority>
  </url>
</urlset>