update

src/app/[...slug]/page.tsx

@@ -30,7 +30,7 @@ const cachedFindByPath = cache(async (path: string) => {
 
 // https://nextjs.org/docs/app/building-your-application/data-fetching/fetching-caching-and-revalidating#opting-out-of-data-caching
 export async function generateMetadata({ params: { slug }}: { params: { slug: Array<string> }}): Promise<Metadata> {
-  const sluggized = await sluggize(slug, '');
+  const sluggized = await sluggize(slug);
   const content = await cachedFindByPath(sluggized);
   return generateForArticleOrPage(sluggized ,content.body);
 }
@@ -45,7 +45,7 @@ async function run(req: any): Promise<any> {
 }
 
 async function get(req: any) {
-  let path = req.params.slug.join("/");
+  let path = sluggize(req.params.slug);
   // TODO move utils & write testcode
   if (!path.startsWith("/")) {
     path = "/" + path;

src/utils/slug.ts

@@ -1,5 +1,7 @@
+
+// FIXME: messy code (I'm tired to fight wiht TS type)
 export function sluggize(
-    slug: any,  // NOTE: Next.js request context is any.
+    slug: Array<string> | string,  // NOTE: Next.js request context seems <any>.
     prefix: string | undefined = undefined,
     fallback: string | undefined = undefined
   ) {
@@ -9,8 +11,8 @@ export function sluggize(
         const s = slug as Array<string>;
         const arr = [p].concat(s);
         return arr.join('/');
-       } else {
-        return fallback;
+      } else {
+        return slug;
       }
     } catch {
       return fallback;