Fix the sitemap indexes

astro/src/pages/sitemap/blogs.xml.ts

@@ -21,9 +21,28 @@ export const GET = (async () => {
     let sitemaps: SitemapIndex[] = [];
 
     for (let i = 0; i < pages; i++) {
+        const selectedBlogs = blogs.slice(
+            ((Number(i + 1) - 1) * settings.sitemap.perPage),
+            Number(i + 1) * settings.sitemap.perPage - 1
+        );
+
+        let dates = [
+            settings.sitemap.lastModified,
+            settings.blog.lastModified,
+            settings.website.lastModified
+        ];
+
+        selectedBlogs.forEach((blog) => {
+            dates.push(blog.lastModified);
+        });
+
+        const lastModified = dates.sort((a: Date, b: Date) => {
+            return b.getTime() - a.getTime();
+        });
+
         sitemaps.push({
             url: `/sitemap/blogs-${i + 1}.xml`,
-            lastModified: new Date()
+            lastModified: lastModified[0]
         });
     }