remark-mdx

What is remark-mdx?

The remark-mdx npm package is a plugin for remark, a markdown processor powered by plugins part of the unified collective. It enables MDX syntax in markdown documents processed by remark. MDX is an authorable format that lets you seamlessly write JSX in your markdown documents. This package allows you to parse and serialize MDX files, making it possible to use MDX with the remark ecosystem.

What are remark-mdx's main functionalities?

Parsing MDX syntax

This feature allows you to parse strings of MDX and transform them into a markdown abstract syntax tree (AST).

const remark = require('remark');
const remarkMdx = require('remark-mdx');

remark().use(remarkMdx).processSync('<h1>Hello, MDX!</h1>').toString();

Serializing MDX

This feature enables you to serialize the markdown AST back into a string of MDX, which can then be saved to a file or processed further.

const remark = require('remark');
const remarkMdx = require('remark-mdx');
const vfile = require('to-vfile');

const file = vfile.readSync('example.mdx');
const result = remark().use(remarkMdx).processSync(file).toString();
console.log(result);

Other packages similar to remark-mdx

remark

Remark is the core library that powers the remark ecosystem, which includes remark-mdx. It is a markdown processor that can be extended with plugins but does not support MDX syntax out of the box.

rehype

Rehype is another processor in the unified collective that works with HTML instead of markdown. It can be used in conjunction with remark-mdx to transform the markdown AST into a rehype (HTML) AST and manipulate it further.

README

remark-mdx

remark plugin to support the MDX syntax (JSX, expressions, import/exports).

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • unified().use(remarkMdx)
• Syntax
• Syntax tree
• Types
• Security
• Contribute
• License

What is this?

This package is a remark plugin to support the MDX syntax.

When should I use this?

This plugin is useful if you’re dealing with the MDX syntax and integrating with remark, rehype, and the rest of unified. Some example use cases are when you want to lint the syntax or compile it to something other that JavaScript.

remark is an AST (abstract syntax tree) based transform project. The layer under remark is called mdast, which is just the syntax tree without the convention on how to transform. mdast is useful when transforming to other formats. Another layer underneath is micromark, which is just the parser and has support for concrete tokens. micromark is useful for linting and formatting. remark-mdx is a small wrapper to integrate all of these. Its parts can be used separately.

Typically though, you’d want to move a layer up: @mdx-js/mdx. That package is the core compiler for turning MDX into JavaScript which gives you the most control. Or even higher: if you’re using a bundler (webpack, Rollup, esbuild), or a site builder (Gatsby, Next.js) or build system (Vite, WMR) which comes with a bundler, you’re better off using an integration: see § Integrations.

Install

This package is ESM only: Node 12+ is needed to use it and it must be imported instead of required.

npm:

npm install remark-mdx@next

yarn:

yarn add remark-mdx@next

Use

import {remark} from 'remark'
import remarkMdx from 'remark-mdx'

const file = remark()
  .use(remarkMdx)
  .processSync('import a from "b"\n\na <b /> c {1 + 1} d')

console.log(String(file))

Yields:

import a from "b"

a <b/> c {1 + 1} d

API

This package exports no identifiers. The default export is remarkMdx.

unified().use(remarkMdx)

Configures remark so that it can parse and serialize MDX (JSX, expressions, import/exports). It doesn’t do anything with the syntax: you can create your own plugin to transform them.

Syntax

This plugin applies several micromark extensions to parse the syntax. See their readmes for parse details:

• micromark-extension-mdx-expression — expressions ({1 + 1})
• micromark-extension-mdx-jsx — JSX (<div />)
• micromark-extension-mdxjs-esm — ESM (export x from 'y')
• micromark-extension-mdx-md — Turn off HTML, autolinks, and indented code

Syntax tree

This plugin applies several mdast utilities to build and serialize the AST. See their readmes for the node types supported in the tree:

• mdast-util-mdx-expression — expressions ({1 + 1})
• mdast-util-mdx-jsx — JSX (<div />)
• mdast-util-mdxjs-esm — ESM (export x from 'y')

Types

This package is fully typed with TypeScript.

If you’re working with the syntax tree, make sure to import this plugin somewhere in your types, as that registers the new node types in the tree.

/**
 * @typedef {import('remark-mdx')}
 */

import {visit} from 'unist-util-visit'

export default function myRemarkPlugin() => {
  /** @param {import('@types/mdast').Root} tree */
  return (tree) => {
    visit(tree, (node) => {
      // `node` can now be one of the nodes for JSX, expressions, or ESM.
    })
  }
}

Alternatively, in TypeScript, do:

/// <reference types="remark-mdx" />

import type {Root} from '@types/mdast'
import {visit} from 'unist-util-visit'

export default function myRemarkPlugin() => {
  return (tree: Root) => {
    visit(tree, (node) => {
      // `node` can now be one of the nodes for JSX, expressions, or ESM.
    })
  }
}

Security

See § Security on our website for information.

Contribute

See § Contribute on our website for ways to get started. See § Support for ways to get help.

This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.

License

MIT © Titus Wormer