<url>
 <loc>http://www.jouypub.com/</loc>
 <lastmod>2019-05-01</lastmod>
 <changefreq>daily</changefreq>
 <priority>0.5</priority>
</url>

> npm install --save sitemap

const express = require('express')
const sm = require('sitemap');

router.get('/sitemap.xml', function (req, res) {
 let pageRequest = Object.create({});
 pageRequest.pageSize = -1;
 pageRequest.pageNum = 1;
 api.post('/article/list', pageRequest, function (result) {
  let urls = [];
  for (let article in result) {
   urls.push({
    url: article.url,
    changefreq: 'daily',
    lastmodrealtime: true,
    priority: 1,
    lastmod: article.updateTime
   });
  }

  let sitemap = sm.createSitemap({
   hostname: 'http://invest.jouypub.com',
   cacheTime: 600000, // 600sec, cache purge period
   urls: urls
  });

  sitemap.toXML(function (err, xml) {
   if (err) {
    console.log(err);
    return res.status(500).end();
   }
   res.header('Content-Type', 'application/xml');
   res.send(xml);
  });
 });
});