jaster.xyz/src/content.config.ts

import { glob } from "astro/loaders";
import { defineCollection, z } from "astro:content";

const blog = defineCollection({
  loader: glob({ base: "./src/content/blog", pattern: "**/*.{md,mdx}" }),
  // Type-check frontmatter using a schema
  schema: ({ image }) =>
    z.object({
      title: z.string(),
      description: z.string().optional(),
      pubDate: z.coerce.date(),
      image: image(),
    }),
});

export const collections = { blog };