Astro content collections not working

[jueewo]

I'm trying to get content collections running using SSR with Deno. Using the deno-astro-template Astro works, but the collections is empty:

• File: src/pages/blog/index.astro

---
import Layout from "../../layouts/Layout.astro" //"../../layouts/main.astro";
import { getCollection, getEntry } from "astro:content";

const blog_carddata = (await getCollection("blog"));
---

<Layout>
<div>CARDDATA: {blog_carddata}</div>
</Layout>

• blog dir and mdx files are existing in: src/content/blog/xx.mdx

• config.ts with

import { defineCollection, z } from "astro:content";
const blogCollection = defineCollection({..});
export const collections = {
  blog: blogCollection,
}