Add changeFrequency and priority attributes to sitemaps (#48484)

Closes #48479. 

Couldn't find the source for the Next.js beta docs, so I didn't add documentation.

Co-authored-by: Jiachi Liu <[email protected]>

Author: LuudJanssen

packages/next/src/build/webpack/loaders/metadata/resolve-route-data.test.ts

@@ -82,6 +82,8 @@ describe('resolveRouteData', () => {
           {
             url: 'https://example.com',
             lastModified: '2021-01-01',
+            changeFrequency: 'weekly',
+            priority: 0.5,
           },
         ])
       ).toMatchInlineSnapshot(`
@@ -90,6 +92,8 @@ describe('resolveRouteData', () => {
         <url>
         <loc>https://example.com</loc>
         <lastmod>2021-01-01</lastmod>
+        <changefreq>weekly</changefreq>
+        <priority>0.5</priority>
         </url>
         </urlset>
         "

packages/next/src/build/webpack/loaders/metadata/resolve-route-data.ts

@@ -47,19 +47,33 @@ export function resolveSitemap(data: MetadataRoute.Sitemap): string {
   let content = ''
   content += '<?xml version="1.0" encoding="UTF-8"?>\n'
   content += '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">\n'
+
   for (const item of data) {
     content += '<url>\n'
     content += `<loc>${item.url}</loc>\n`
+
     if (item.lastModified) {
-      content += `<lastmod>${
+      const serializedDate =
         item.lastModified instanceof Date
           ? item.lastModified.toISOString()
           : item.lastModified
-      }</lastmod>\n`
+
+      content += `<lastmod>${serializedDate}</lastmod>\n`
+    }
+
+    if (item.changeFrequency) {
+      content += `<changefreq>${item.changeFrequency}</changefreq>\n`
     }
+
+    if (typeof item.priority === 'number') {
+      content += `<priority>${item.priority}</priority>\n`
+    }
+
     content += '</url>\n'
   }
+
   content += '</urlset>\n'
+
   return content
 }
 

packages/next/src/lib/metadata/types/metadata-interface.ts

@@ -558,6 +558,15 @@ type RobotsFile = {
 type SitemapFile = Array<{
   url: string
   lastModified?: string | Date
+  changeFrequency?:
+    | 'always'
+    | 'hourly'
+    | 'daily'
+    | 'weekly'
+    | 'monthly'
+    | 'yearly'
+    | 'never'
+  priority?: number
 }>
 
 type ResolvingMetadata = Promise<ResolvedMetadata>

test/e2e/app-dir/metadata-dynamic-routes/app/sitemap.ts

@@ -6,6 +6,8 @@ export default function sitemap(): MetadataRoute.Sitemap {
     {
       url: 'https://example.com',
       lastModified: '2021-01-01',
+      changeFrequency: 'weekly',
+      priority: 0.5,
     },
     {
       url: 'https://example.com/about',

test/e2e/app-dir/metadata-dynamic-routes/index.test.ts

@@ -55,6 +55,8 @@ createNextDescribe(
           <url>
           <loc>https://example.com</loc>
           <lastmod>2021-01-01</lastmod>
+          <changefreq>weekly</changefreq>
+          <priority>0.5</priority>
           </url>
           <url>
           <loc>https://example.com/about</loc>