Dynamic Routes

Generate many pages from a single markdown file and dynamic data. Useful for blogs, package docs, or any data-driven pages.

Basic Setup

Create a template file with parameter in brackets and a paths loader:

.
└─ packages/
   ├─ [pkg].md           # Route template
   └─ [pkg].paths.js     # Paths loader

The paths loader exports a paths method returning route parameters:

// packages/[pkg].paths.js
export default {
  paths() {
    return [
      { params: { pkg: 'foo' } },
      { params: { pkg: 'bar' } },
      { params: { pkg: 'baz' } },
    ];
  },
};

Generated pages:

• /packages/foo.html
• /packages/bar.html
• /packages/baz.html

Multiple Parameters

.
└─ packages/
   ├─ [pkg]-[version].md
   └─ [pkg]-[version].paths.js

// packages/[pkg]-[version].paths.js
export default {
  paths() {
    return [
      { params: { pkg: 'foo', version: '1.0.0' } },
      { params: { pkg: 'foo', version: '2.0.0' } },
      { params: { pkg: 'bar', version: '1.0.0' } },
    ];
  },
};

Dynamic Path Generation

From local files:

// packages/[pkg].paths.js
import fs from 'node:fs';

export default {
  paths() {
    return fs.readdirSync('packages').map((pkg) => ({
      params: { pkg },
    }));
  },
};

From remote API:

// packages/[pkg].paths.js
export default {
  async paths() {
    const packages = await fetch('https://api.example.com/packages').then((r) =>
      r.json(),
    );

    return packages.map((pkg) => ({
      params: {
        pkg: pkg.name,
        version: pkg.version,
      },
    }));
  },
};

Accessing Params in Page

Template globals:

<!-- packages/[pkg].md -->

# Package: {{ $params.pkg }}

Version: {{ $params.version }}

In script:

<script setup>
import { useData } from 'vitepress';
const { params } = useData();
</script>

<template>
  <h1>{{ params.pkg }}</h1>
</template>

Passing Content

For heavy content (raw markdown/HTML from CMS), use content instead of params to avoid bloating the client bundle:

// posts/[slug].paths.js
export default {
  async paths() {
    const posts = await fetch('https://cms.example.com/posts').then((r) =>
      r.json(),
    );

    return posts.map((post) => ({
      params: { slug: post.slug },
      content: post.content, // Raw markdown or HTML
    }));
  },
};

Render content in template:

## <!-- posts/[slug].md -->

## title: {{ $params.title }}

<!-- @content -->

The <!-- @content --> placeholder is replaced with the content from the paths loader.

Watch Option

Auto-rebuild when template or data files change:

// posts/[slug].paths.js
export default {
  watch: ['./templates/**/*.njk', '../data/**/*.json'],

  paths(watchedFiles) {
    const dataFiles = watchedFiles.filter((f) => f.endsWith('.json'));

    return dataFiles.map((file) => {
      const data = JSON.parse(fs.readFileSync(file, 'utf-8'));
      return {
        params: { slug: data.slug },
        content: renderTemplate(data),
      };
    });
  },
};

Complete Example: Blog

// posts/[slug].paths.js
import fs from 'node:fs';
import matter from 'gray-matter';

export default {
  watch: ['./posts/*.md'],

  paths(files) {
    return files
      .filter((f) => !f.includes('[slug]'))
      .map((file) => {
        const content = fs.readFileSync(file, 'utf-8');
        const { data, content: body } = matter(content);
        const slug = file.match(/([^/]+)\.md$/)[1];

        return {
          params: {
            slug,
            title: data.title,
            date: data.date,
          },
          content: body,
        };
      });
  },
};

## <!-- posts/[slug].md -->

## layout: doc

# {{ $params.title }}

<time>{{ $params.date }}</time>

<!-- @content -->

Key Points

• Template file uses [param] syntax in filename
• Paths loader file must be named [param].paths.js or .ts
• paths() returns array of { params: {...}, content?: string }
• Use $params in templates or useData().params in scripts
• Use content for heavy data to avoid client bundle bloat
• watch enables HMR for template/data file changes

Contributors

XiSenao

Changelog

Last edited 10 days ago

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2f55cfe-feat(ai-instructions): add skill definitions package