Gatsby MDX

MDX integration with Gatsby for ambitious projects.

Initial Setup

npm install gatsby-mdx @mdx-js/mdx @mdx-js/tag

then add gatsby-mdx to your gatsby-config.js in the plugins section.

module.exports = {
  siteMetadata: {
    title: `My Ambitious Project`
  },
  plugins: [`gatsby-mdx`]
};

Note: gatsby-mdx is only compatible with Gatsby version 2 or newer.

Writing Pages in MDX

Add an .mdx file in the src/pages directory. It "Just Works".

# My first MDX Page

some awesome content

Plugin Options

File Extensions

gatsby-mdx can apply to different file extensions. By default it conservatively applies to only .mdx files, but can also be made to apply to .md files.

module.exports = {
  plugins: [
    {
      resolve: `gatsby-mdx`,
      options: {
        extensions: [".mdx", ".md"]
      }
    }
  ]
};

Default Layouts

MDX supports layouts using the default export as such:

export default ({ children }) => (
  <div>
    <h1>My Layout</h1>
    <div>{children}</div>
  </div>
)


# My MDX

some content

or as an import:

import PageLayout from './src/components/page-layout';
export PageLayout

# My MDX

some content

Sometimes you don't want to include the layout in every file, so gatsby-mdx offers the option to set default layouts in the gatsby-config.js plugin config. Set the key to the name set in the gatsby-source-filesystem config. If no matching default layout is found, the default default layout is used.

You can also set options.defaultLayout if you only want to use one layout for all MDX pages.

module.exports = {
  siteMetadata: {
    title: `Gatsby MDX Kitchen Sink`
  },
  plugins: [
    {
      resolve: `gatsby-mdx`,
      options: {
        defaultLayouts: {
          posts: require.resolve("./src/components/posts-layout.js"),
          default: require.resolve("./src/components/default-page-layout.js")
        }
      }
    },
    {
      resolve: `gatsby-source-filesystem`,
      options: {
        name: `posts`,
        path: `${__dirname}/src/posts/`
      }
    }
  ]
};

GraphQL

MDX files can be queried with allMdx on the root query. Like gatsby-transformer-remark, this plugin adds fields to the Mdx node including excerpt, headings, timeToRead, and wordCount.

All static exports – values that would be valid JSON – are queryable through the exports field.

query MDXQuery {
  allMdx {
    edges {
      node {
        relativePath
        fileAbsolutePath
        fileNode {
          name
        }
        timeToRead
        frontmatter {
          title
        }
        exports {
          author
        }
      }
    }
  }
}

Programmatically Creating Pages

Pages can be created programmatically by combining gatsby-source-filesystem in gatsby-config.js with some createPage calls.

# gatsby-config.js
module.exports = {
  plugins: [
  `gatsby-mdx`,
    {
      resolve: "gatsby-source-filesystem",
      options: {
        name: "posts",
        path: `${__dirname}/content/`
      }
    }
  ]
};

# gatsby-node.js
exports.createPages = ({ graphql, actions }) => {
  const { createPage } = actions;
  return new Promise((resolve, reject) => {
    resolve(
      graphql(
        `
          {
            allMdx {
              edges {
                node {
                  fileAbsolutePath
                  fileNode {
                    name
                  }
                }
              }
            }
          }
        `
      ).then(result => {
        if (result.errors) {
          console.log(result.errors);
          reject(result.errors);
        }

        // Create blog posts pages.
        result.data.allMdx.edges.forEach(({ node }) => {
          createPage({
            path: `/non-page/${node.fileNode.name}`,
            component: node.fileAbsolutePath, //blogPost,
            context: { absPath: node.absolutePath }
          });
        });
      })
    );
  });
};

Getting Ambitious

Using Design System Components

Using MDX, you can replace every HTML element that Markdown renders with a custom implementation. This allows you to use a set of design system components when rendering Markdown.

// src/components/layout.js

import { MDXProvider } from "@mdx-js/tag";
import * as DesignSystem from "your-design-system";

export default function Layout({ children }) {
  return (
    <MDXProvider
      components={{
        // Map HTML element tag to React component
        h1: DesignSystem.H1,
        h2: DesignSystem.H2,
        h3: DesignSystem.H3,
        // Or define component inline
        p: props => <p {...props} style={{ color: "rebeccapurple" }} />
      }}
    >
      {children}
    </MDXProvider>
  );
}

Editable Code Blocks

To make every markdown code block an editable live example, you can pass in a custom code element to MDXProvider.

import React, {Component} from "react";
import { LiveProvider, LiveEditor, LiveError, LivePreview } from "react-live";
import { MDXProvider } from '@mdx-js/tag'

const MyCodeComponent = ({ children, ...props }) => (
  <LiveProvider code={children}>
    <LiveEditor />
    <LiveError />
    <LivePreview />
  </LiveProvider>
);

export default MyPageLayout extends Component {
  render() {
    return <MDXProvider components={{code: MyCodeComponent}}>
      <div>{this.props.children}</div>
    </MDXProvider>
  }
}