Sitemap.xml: Add last updated date

Get each location last photo created date as the latest content added

src/routes/sitemap.xml.js

@@ -34,6 +34,8 @@ const render = (pages, locations) => {
     <url>
         <loc>${baseURL}/location/${loc.country.slug}/${loc.slug}</loc>
         <priority>1</priority>
+        <lastmod>${loc.updated}</lastmod>
+        <changefreq>weekly</changefreq>
     </url>`).join('\n')}
 </urlset>`
 }
@@ -45,13 +47,24 @@ export async function get (req, res, next) {
 
     // Get locations
     const locationsReq = await fetch(`${apiEndpoints.rest}/items/locations?fields=slug,country.slug`)
-    const locations = await locationsReq.json()
+    const locationsData = await locationsReq.json()
+    const locations = locationsData.data
+
+    // Add last modified date to each location from its last photo
+    const updatedLocations = locations.map(async (location, i) => {
+        const latestPhotoReq = await fetch(`${apiEndpoints.rest}/items/photos?fields=created_on&limit=1&sort=created_on&filter[location.slug][rlike]=%${location.slug}`)
+        const latestPhotoData = await latestPhotoReq.json()
+        const latestPhoto = latestPhotoData.data[0]
+        location.updated = latestPhoto.created_on
+        return location
+    })
+    await Promise.all(updatedLocations)
 
     // Set headers
     res.setHeader('Cache-Control', 'max-age=0, s-max-age=600') // 10 minutes
     res.setHeader('Content-Type', 'application/rss+xml')
 
     // Render sitemap
-    const sitemap = render(pages, locations.data)
+    const sitemap = render(pages, locations)
     res.end(sitemap)
 }