Content Collections

Content Collections

Status: Production Ready ✅ Last Updated: 2025-11-07 Dependencies: None Latest Versions: @content-collections/​[email protected], @content-collections/​[email protected], [email protected]

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What is Content Collections?

Content Collections transforms local content files (Markdown/​MDX) into type-safe TypeScript data with automatic validation at build time.

Problem it solves: Manual content parsing, lack of type safety, runtime errors from invalid frontmatter.

How it works:

1. Define collections in content-collections.ts (name, directory, Zod schema)
2. CLI/​plugin scans filesystem, parses frontmatter, validates against schema
3. Generates TypeScript modules in .content-collections/​generated/
4. Import collections: import { allPosts } from "content-collections"

Perfect for: Blogs, documentation sites, content-heavy apps with Cloudflare Workers, Vite, Next.js.

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Quick Start (5 Minutes)

1. Install Dependencies

# Bun (recommended)
bun add -d @content-collections/​core @content-collections/​vite zod

# npm
npm install -D @content-collections/​core @content-collections/​vite zod

# pnpm
pnpm add -D @content-collections/​core @content-collections/​vite zod

2. Configure TypeScript Path Alias

Add to tsconfig.json:

{
  "compilerOptions": {
    "paths": {
      "content-collections": ["./​.content-collections/​generated"]
    }
  }
}

1. Configure Vite Plugin

Add to vite.config.ts:

import { defineConfig } from "vite";
import react from "@vitejs/​plugin-react";
import contentCollections from "@content-collections/​vite";

export default defineConfig({
  plugins: [
    react(),
    contentCollections(), // MUST come after react()
  ],
});

4. Update .gitignore

.content-collections/

5. Create Collection Config

Create content-collections.ts in project root:

import { defineCollection, defineConfig } from "@content-collections/​core";
import { z } from "zod";

const posts = defineCollection({
  name: "posts",
  directory: "content/​posts",
  include: "*.md",
  schema: z.object({
    title: z.string(),
    date: z.string(),
    description: z.string(),
    content: z.string(),
  }),
});

export default defineConfig({
  collections: [posts],
});

6. Create Content Directory

mkdir -p content/​posts

Create content/​posts/​first-post.md:

---
title: My First Post
date: 2025-11-07
description: Introduction to Content Collections
---

# My First Post

Content goes here...

7. Import and Use

import { allPosts } from "content-collections";

console.log(allPosts); // Fully typed!

Result: Type-safe content with autocomplete, validation, and HMR.

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Critical Rules

✅ Always Do:

1. Add path alias to tsconfig.json - Required for imports to work
2. Add .content-collections to .gitignore - Generated files shouldn't be committed
3. Use Standard Schema validators - Zod, Valibot, ArkType supported
4. Include content field in schema - Required for frontmatter parsing
5. Await compileMDX in transforms - MDX compilation is async
6. Put contentCollections() after react() in Vite - Plugin order matters

❌ Never Do:

1. Commit .content-collections directory - Always generated, never committed
2. Use non-standard validators - Must support StandardSchema spec
3. Forget to restart dev server after config changes - Required for new collections
4. Use sync transforms with async operations - Transform must be async
5. Double-wrap path alias - Use content-collections not ./​content-collections
6. Import from wrong package - @content-collections/​core for config, content-collections for data

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Known Issues Prevention

Issue #1: Module not found: 'content-collections'

Error: Cannot find module 'content-collections' or its corresponding type declarations

Why it happens: Missing TypeScript path alias configuration.

Prevention:

Add to tsconfig.json:

{
  "compilerOptions": {
    "paths": {
      "content-collections": ["./​.content-collections/​generated"]
    }
  }
}

Restart TypeScript server in VS Code: Cmd+Shift+P → "TypeScript: Restart TS Server"

Source: Common user error

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Issue #2: Vite Constant Restart Loop

Error: Dev server continuously restarts, infinite loop.

Why it happens: Vite watching .content-collections directory changes, which triggers regeneration.

Prevention:

1. Add to .gitignore:

.content-collections/

1. Add to vite.config.ts (if still happening):

export default defineConfig({
  server: {
    watch: {
      ignored: ["**/​.content-collections/​**"],
    },
  },
});

Source: GitHub Issue #591 (TanStack Start)

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Issue #3: Transform Types Not Reflected

Error: TypeScript types don't match transformed documents.

Why it happens: TypeScript doesn't automatically infer transform function return type.

Prevention:

Explicitly type your transform return:

const posts = defineCollection({
  name: "posts",
  // ... schema
  transform: (post): PostWithSlug => ({ // Type the return!
    ...post,
    slug: post._meta.path.replace(/\.md$/, ""),
  }),
});

type PostWithSlug = {
  // ... schema fields
  slug: string;
};

Source: GitHub Issue #396

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Issues #4-8: Advanced Troubleshooting

Additional issues covered in references/​advanced-troubleshooting.md:

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Configuration Patterns

For detailed schema patterns (dates, tags, validation), load references/​schema-patterns.md.

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React Component Integration

Using Collections in React

import { allPosts } from "content-collections";

export function BlogList() {
  return (
    <ul>
      {allPosts.map((post) => (
        <li key={post._meta.path}>
          <h2>{post.title}</​h2>
          <p>{post.description}</​p>
          <time>{post.date}</​time>
        </​li>
      ))}
    </​ul>
  );
}

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Rendering MDX Content

import { MDXContent } from "@content-collections/​mdx/​react";

export function BlogPost({ post }: { post: { mdx: string } }) {
  return (
    <article>
      <MDXContent code={post.mdx} />
    </​article>
  );
}

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Cloudflare Workers Deployment

Content Collections is perfect for Cloudflare Workers (build-time only, no runtime filesystem). Use template templates/​wrangler.toml for config.

Pattern: vite build → wrangler deploy (Vite plugin handles content-collections automatically)

For detailed deployment guide, load references/​deployment-guide.md.

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Bundled Resources

Templates (9 copy-paste files)

content-collections.ts, content-collections-multi.ts, content-collections-mdx.ts, tsconfig.json, vite.config.ts, BlogList.tsx, BlogPost.tsx, blog-post.md, wrangler.toml

Scripts

init-content-collections.sh - One-command automated setup

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Dependencies

Required

{
  "devDependencies": {
    "@content-collections/​core": "^0.12.0",
    "@content-collections/​vite": "^0.2.7",
    "zod": "^3.23.8"
  }
}

Optional (MDX)

{
  "devDependencies": {
    "@content-collections/​markdown": "^0.1.4",
    "@content-collections/​mdx": "^0.2.2",
    "shiki": "^1.0.0"
  }
}

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Official Documentation

• Official Site: https://www.content-collections.dev
• Documentation: https://www.content-collections.dev/docs
• GitHub: https://github.com/sdorra/content-collections
• Vite Plugin: https://www.content-collections.dev/docs/vite
• MDX Integration: https://www.content-collections.dev/docs/mdx

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Package Versions (Verified 2025-11-07)

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Quick Troubleshooting

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When to Load References

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Complete Setup Checklist

• Installed @content-collections/​core and @content-collections/​vite
• Installed zod for schema validation
• Added path alias to tsconfig.json
• Added contentCollections() to vite.config.ts (after react())
• Added .content-collections/ to .gitignore
• Created content-collections.ts in project root
• Created content directory (e.g., content/​posts/)
• Defined collection with Zod schema
• Created first content file with frontmatter
• Imported collection in React component
• Verified types work (autocomplete)
• Tested hot reloading (change content file)