mdx-bundler 🦤

Compile and bundle your MDX files and their dependencies. FAST.

--- [![Build Status][build-badge]][build] [![Code Coverage][coverage-badge]][coverage] [![version][version-badge]][package] [![downloads][downloads-badge]][npmtrends] [![MIT License][license-badge]][license] [![All Contributors][all-contributors-badge]](#contributors-) [![PRs Welcome][prs-badge]][prs] [![Code of Conduct][coc-badge]][coc] ## The problem You have a string of MDX and various TS/JS files that it uses and you want to get a bundled version of these files to eval in the browser. ## This solution This is an async function that will compile and bundle your MDX files and their dependencies. It uses [MDX v3](https://mdxjs.com/blog/v3/) and [esbuild](https://esbuild.github.io/), so it's VERY fast and supports TypeScript files (for the dependencies of your MDX files). Your source files could be local, in a remote github repo, in a CMS, or wherever else and it doesn't matter. All `mdx-bundler` cares about is that you pass it all the files and source code necessary and it will take care of bundling everything for you. ### FAQ:

"What's so cool about MDX?"

[MDX](https://mdxjs.com/) enables you to combine terse markdown syntax for your content with the power of JSX components. For content-heavy sites, writing the content with straight-up HTML can be annoyingly verbose. Often people solve this using a WSYWIG editor, but too often those fall short in mapping the writer's intent to HTML. Many people prefer using markdown to express their content source and have that parsed into HTML to be rendered. The problem with using Markdown for your content is if you want to have some interactivity embedded into your content, you're pretty limited. You either need to insert an element that JavaScript targets (which is annoyingly indirect), or you can use an `iframe` or something. As previously stated, [MDX](https://mdxjs.com/) enables you to combine terse markdown syntax for your content with the power of JSX components. So you can import a JSX component and render it within the markdown itself. It's the best of both worlds.

"How is this different from next-mdx-remote?"

`mdx-bundler` actually bundles dependencies of your MDX files. For example, this won't work with `next-mdx-remote`, but it will with `mdx-bundler`: ```md --- title: Example Post published: 2021-02-13 description: This is some description --- # Wahoo import Demo from './demo' Here's a **neat** demo: ``` `next-mdx-remote` chokes on that import because it's not a bundler, it's just a compiler. `mdx-bundler` is an MDX compiler and bundler. That's the difference.

"How is this different from the mdx plugins for webpack or rollup?"

Those tools are intended to be run "at build time" and then you deploy the built version of your files. This means if you have some content in MDX and want to make a typo change, you have to rebuild and redeploy the whole site. This also means that every MDX page you add to your site will increase your build-times, so it doesn't scale all that well. `mdx-bundler` can definitely be used at build-time, but it's more powerfully used as a runtime bundler. A common use case is to have a route for your MDX content and when that request comes in, you load the MDX content and hand that off to `mdx-bundler` for bundling. This means that `mdx-bundler` is infinitely scalable. Your build won't be any longer regardless of how much MDX content you have. Also, `mdx-bundler` is quite fast, but to make this on-demand bundling even faster, you can use appropriate cache headers to avoid unnecessary re-bundling. Webpack/rollup/etc also require that all your MDX files are on the local filesystem to work. If you want to store your MDX content in a separate repo or CMS, you're kinda out of luck or have to do some build-time gymnastics to get the files in place for the build. With `mdx-bundler`, it doesn't matter where your MDX content comes from, you can bundle files from anywhere, you're just responsible for getting the content into memory and then you hand that off to `mdx-bundler` for bundling.

"Does this work with Remix/Gatsby/Next/CRA/etc?"

Totally. It works with any of those tools. Depending on whether your meta-framework supports server-side rendering, you'll implement it differently. You might decide to go with a built-time approach (for Gatsby/CRA), but as mentioned, the true power of `mdx-bundler` comes in the form of on-demand bundling. So it's best suited for SSR frameworks like Remix/Next.

"Can I use this other JSX libraries other than React?"

Yes! If JSX runtime you want to use is mentioned here - https://mdxjs.com/docs/getting-started/#jsx, it's guaranteed to work. Libraries, such as `hono` which has `react` compatible API also works. Check to [Other JSX runtimes](#other-jsx-runtimes) to get started.

"Why the dodo bird emoji? 🦤"

Why not?

"Why is esbuild a peer dependency?"

esbuild provides a service written in GO that it interacts with. Only one instance of this service can run at a time and it must have an identical version to the npm package. If it was a hard dependency you would only be able to use the esbuild version mdx-bundler uses.

## Table of Contents - [Installation](#installation) - [Usage](#usage) - [Options](#options) - [Returns](#returns) - [Types](#types) - [Component Substitution](#component-substitution) - [Frontmatter and const](#frontmatter-and-const) - [Accessing named exports](#accessing-named-exports) - [Image Bundling](#image-bundling) - [Bundling a file.](#bundling-a-file) - [Custom Components in Downstream Files](#custom-components-in-downstream-files) - [Known Issues](#known-issues) - [Inspiration](#inspiration) - [Other Solutions](#other-solutions) - [Issues](#issues) - [🐛 Bugs](#-bugs) - [💡 Feature Requests](#-feature-requests) - [Contributors ✨](#contributors-) - [LICENSE](#license) ## Installation This module is distributed via [npm][npm] which is bundled with [node][node] and should be installed as one of your project's `dependencies`: ``` npm install --save mdx-bundler esbuild ``` One of mdx-bundler's dependencies requires a working [node-gyp][node-gyp] setup to be able to install correctly. ## Usage ```typescript import {bundleMDX} from 'mdx-bundler' const mdxSource = ` --- title: Example Post published: 2021-02-13 description: This is some description --- # Wahoo import Demo from './demo' Here's a **neat** demo: `.trim() const result = await bundleMDX({ source: mdxSource, files: { './demo.tsx': ` import * as React from 'react' function Demo() { return

Neat demo!

} export default Demo `, }, }) const {code, frontmatter} = result ``` From there, you send the `code` to your client, and then: ```jsx import * as React from 'react' import {getMDXComponent} from 'mdx-bundler/client' function Post({code, frontmatter}) { // it's generally a good idea to memoize this function call to // avoid re-creating the component every render. const Component = React.useMemo(() => getMDXComponent(code), [code]) return ( <>

{frontmatter.title}

{frontmatter.description}

) } ``` Ultimately, this gets rendered (basically): ```html

This is the title

This is some description

Wahoo

Here's a neat demo:

Neat demo!

``` ### Options #### source The `string` source of your MDX. _Can not be set if `file` is set_ #### file The path to the file on your disk with the MDX in. You will probably want to set [cwd](#cwd) as well. _Can not be set if `source` is set_ #### files The `files` config is an object of all the files you're bundling. The key is the path to the file (relative to the MDX source) and the value is the string of the file source code. You could get these from the filesystem or from a remote database. If your MDX doesn't reference other files (or only imports things from `node_modules`), then you can omit this entirely. #### mdxOptions This allows you to modify the built-in MDX configuration (passed to `@mdx-js/esbuild`). This can be helpful for specifying your own remarkPlugins/rehypePlugins. The function is passed the default mdxOptions and the frontmatter. ```ts bundleMDX({ source: mdxSource, mdxOptions(options, frontmatter) { // this is the recommended way to add custom remark/rehype plugins: // The syntax might look weird, but it protects you in case we add/remove // plugins in the future. options.remarkPlugins = [...(options.remarkPlugins ?? []), myRemarkPlugin] options.rehypePlugins = [...(options.rehypePlugins ?? []), myRehypePlugin] return options }, }) ``` #### esbuildOptions You can customize any of esbuild options with the option `esbuildOptions`. This takes a function which is passed the default esbuild options and the frontmatter and expects an options object to be returned. ```typescript bundleMDX({ source: mdxSource, esbuildOptions(options, frontmatter) { options.minify = false options.target = [ 'es2020', 'chrome58', 'firefox57', 'safari11', 'edge16', 'node12', ] return options }, }) ``` More information on the available options can be found in the [esbuild documentation](https://esbuild.github.io/api/#build-api). It's recommended to use this feature to configure the `target` to your desired output, otherwise, esbuild defaults to `esnext` which is to say that it doesn't compile any standardized features so it's possible users of older browsers will experience errors. #### globals This tells esbuild that a given module is externally available. For example, if your MDX file uses the d3 library and you're already using the d3 library in your app then you'll end up shipping `d3` to the user twice (once for your app and once for this MDX component). This is wasteful and you'd be better off just telling esbuild to _not_ bundle `d3` and you can pass it to the component yourself when you call `getMDXComponent`. Global external configuration options: https://www.npmjs.com/package/@fal-works/esbuild-plugin-global-externals Here's an example: ```tsx // server-side or build-time code that runs in Node: import {bundleMDX} from 'mdx-bundler' const mdxSource = ` # This is the title import leftPad from 'left-pad'

{leftPad("Neat demo!", 12, '!')}

`.trim() const result = await bundleMDX({ source: mdxSource, // NOTE: this is *only* necessary if you want to share deps between your MDX // file bundle and the host app. Otherwise, all deps will just be bundled. // So it'll work either way, this is just an optimization to avoid sending // multiple copies of the same library to your users. globals: {'left-pad': 'myLeftPad'}, }) ``` ```tsx // server-rendered and/or client-side code that can run in the browser or Node: import * as React from 'react' import leftPad from 'left-pad' import {getMDXComponent} from 'mdx-bundler/client' function MDXPage({code}: {code: string}) { const Component = React.useMemo( () => getMDXComponent(result.code, {myLeftPad: leftPad}), [result.code, leftPad], ) return (

) } ``` #### cwd Setting `cwd` (_current working directory_) to a directory will allow esbuild to resolve imports. This directory could be the directory the mdx content was read from or a directory that off-disk mdx should be _run_ in. _content/pages/demo.tsx_ ```typescript import * as React from 'react' function Demo() { return

Neat demo!

} export default Demo ``` _src/build.ts_ ```typescript import {bundleMDX} from 'mdx-bundler' const mdxSource = ` --- title: Example Post published: 2021-02-13 description: This is some description --- # Wahoo import Demo from './demo' Here's a **neat** demo: `.trim() const result = await bundleMDX({ source: mdxSource, cwd: '/users/you/site/_content/pages', }) const {code, frontmatter} = result ``` #### grayMatterOptions This allows you to configure the [gray-matter options](https://github.com/jonschlinkert/gray-matter#options). Your function is passed the current gray-matter configuration for you to modify. Return your modified configuration object for gray matter. ```js bundleMDX({ grayMatterOptions: options => { options.excerpt = true return options }, }) ``` #### bundleDirectory & bundlePath This allows you to set the output directory for the bundle and the public URL to the directory. If one option is set the other must be as well. _The Javascript bundle is not written to this directory and is still returned as a string from `bundleMDX`._ This feature is best used with tweaks to `mdxOptions` and `esbuildOptions`. In the example below `.png` files are written to the disk and then served from `/file/`. This allows you to store assets with your MDX and then have esbuild process them like anything else. _It is recommended that each bundle has its own `bundleDirectory` so that multiple bundles don't overwrite each others assets._ ```ts const {code} = await bundleMDX({ file: '/path/to/site/content/file.mdx', cwd: '/path/to/site/content', bundleDirectory: '/path/to/site/public/file', bundlePath: '/file/', mdxOptions: options => { options.remarkPlugins = [remarkMdxImages] return options }, esbuildOptions: options => { options.loader = { ...options.loader, '.png': 'file', } return options }, }) ``` ### Returns `bundleMDX` returns a promise for an object with the following properties. - `code` - The bundle of your mdx as a `string`. - `frontmatter` - The frontmatter `object` from gray-matter. - `matter` - The whole [object returned by gray-matter](https://github.com/jonschlinkert/gray-matter#returned-object) ### Types `mdx-bundler` supplies complete typings within its own package. `bundleMDX` has a single type parameter which is the type of your frontmatter. It defaults to `{[key: string]: any}` and must be an object. This is then used to type the returned `frontmatter` and the frontmatter passed to `esbuildOptions` and `mdxOptions`. ```ts const {frontmatter} = bundleMDX<{title: string}>({source}) frontmatter.title // has type string ``` ### Component Substitution MDX Bundler passes on [MDX's ability to substitute components](https://mdxjs.com/docs/using-mdx/#components) through the `components` prop on the component returned by `getMDXComponent`. Here's an example that removes _p_ tags from around images. ```tsx import * as React from 'react' import {getMDXComponent} from 'mdx-bundler/client' const Paragraph: React.FC = props => { if (typeof props.children !== 'string' && props.children.type === 'img') { return <>{props.children} } return

} function MDXPage({code}: {code: string}) { const Component = React.useMemo(() => getMDXComponent(code), [code]) return (

) } ``` ### Frontmatter and const You can reference frontmatter meta or consts in the mdx content. ```mdx --- title: Example Post --- export const exampleImage = 'https://example.com/image.jpg' # {frontmatter.title} Image alt text

``` ### Accessing named exports You can use `getMDXExport` instead of `getMDXComponent` to treat the mdx file as a module instead of just a component. It takes the same arguments that `getMDXComponent` does. ```mdx --- title: Example Post --- export const toc = [{depth: 1, value: 'The title'}] # The title ``` ```js import * as React from 'react' import {getMDXExport} from 'mdx-bundler/client' function MDXPage({code}: {code: string}) { const mdxExport = getMDXExport(code) console.log(mdxExport.toc) // [ { depth: 1, value: 'The title' } ] const Component = React.useMemo(() => mdxExport.default, [code]) return } ``` ### Image Bundling With the [cwd](#cwd) and the remark plugin [remark-mdx-images](https://www.npmjs.com/package/remark-mdx-images) you can bundle images in your mdx! There are two loaders in esbuild that can be used here. The easiest is `dataurl` which outputs the images as inline data urls in the returned code. ```js import {remarkMdxImages} from 'remark-mdx-images' const {code} = await bundleMDX({ source: mdxSource, cwd: '/users/you/site/_content/pages', mdxOptions: options => { options.remarkPlugins = [...(options.remarkPlugins ?? []), remarkMdxImages] return options }, esbuildOptions: options => { options.loader = { ...options.loader, '.png': 'dataurl', } return options }, }) ``` The `file` loader requires a little more configuration to get working. With the `file` loader your images are copied to the output directory so esbuild needs to be set to write files and needs to know where to put them plus the url of the folder to be used in image sources. > Each call to `bundleMDX` is isolated from the others. If you set the directory > the same for everything `bundleMDX` will overwrite images without warning. As > a result each _bundle_ needs its own output directory. ```js // For the file `_content/pages/about.mdx` const {code} = await bundleMDX({ source: mdxSource, cwd: '/users/you/site/_content/pages', mdxOptions: options => { options.remarkPlugins = [...(options.remarkPlugins ?? []), remarkMdxImages] return options }, esbuildOptions: options => { // Set the `outdir` to a public location for this bundle. options.outdir = '/users/you/site/public/img/about' options.loader = { ...options.loader, // Tell esbuild to use the `file` loader for pngs '.png': 'file', } // Set the public path to /img/about options.publicPath = '/img/about' // Set write to true so that esbuild will output the files. options.write = true return options }, }) ``` ### Bundling a file. If your MDX file is on your disk you can save some time and code by having `mdx-bundler` read the file for you. Instead of supplying a `source` string you can set `file` to the path of the MDX on disk. Set `cwd` to its folder so that relative imports work. ```js import {bundleMDX} from 'mdx-bundler' const {code, frontmatter} = await bundleMDX({ file: '/users/you/site/content/file.mdx', cwd: '/users/you/site/content/', }) ``` ### Custom Components in Downstream Files To make sure custom components are accessible in downstream MDX files, you can use the `MDXProvider` from `@mdx-js/react` to pass custom components to your nested imports. ``` npm install --save @mdx-js/react ``` ```tsx const globals = { '@mdx-js/react': { varName: 'MdxJsReact', namedExports: ['useMDXComponents'], defaultExport: false, }, }; const { code } = bundleMDX({ source, globals, mdxOptions(options: Record) { return { ...options, providerImportSource: '@mdx-js/react', }; } }); ``` From there, you send the `code` to your client, and then: ```tsx import { MDXProvider, useMDXComponents } from '@mdx-js/react'; const MDX_GLOBAL_CONFIG = { MdxJsReact: { useMDXComponents, }, }; export const MDXComponent: React.FC<{ code: string; frontmatter: Record; }> = ({ code }) => { const Component = useMemo( () => getMDXComponent(code, MDX_GLOBAL_CONFIG), [code], ); return (

{children}

}}> ); }; ``` ### Known Issues ### Other JSX runtimes JSX runtimes mentioned [here](https://mdxjs.com/docs/getting-started/#jsx) are guaranteed to be supported, however any JSX runtime should work without problem, as long as they export their own jsx runtime. For example, `hono` is not mentioned here, but as it has `react` compatible API, it can be used without any issues. To do so, you will have to pass a configuration object and use JSX Component factory. ```tsx const getMDX = (source) => { return bundleMDX({ source, jsxConfig: { jsxLib: { varName: 'HonoJSX', package: 'hono/jsx', }, jsxDom: { varName: 'HonoDOM', package: 'hono/jsx/dom', }, jsxRuntime: { varName: '_jsx_runtime', package: 'hono/jsx/jsx-runtime', }, } }); } // ... import { getMDXComponent } from "mdx-bundler/client/jsx"; import * as HonoJSX from "hono/jsx"; import * as HonoDOM from "hono/jsx/dom"; import * as _jsx_runtime from "hono/jsx/jsx-runtime"; const jsxConfig = { HonoJSX, HonoDOM, _jsx_runtime }; export const MDXComponent: React.FC<{ code: string; }> = ({ code }) => { const Component = useMemo( () => getMDXComponent(code, jsxConfig), [code], ); return (

{children}

}} /> ); }; ``` To use it with others, adjust `jsxConfig` passed to bundler. ```ts const jsxConfig = { jsxLib: { varName: 'HonoJSX', package: 'hono/jsx', }, jsxDom: { varName: 'HonoDOM', package: 'hono/jsx/dom', }, jsxRuntime: { varName: '_jsx_runtime', package: 'hono/jsx/jsx-runtime', }, } ``` and to `getMDXComponent` ```ts const jsxConfig = { HonoJSX, HonoDOM, _jsx_runtime }; ``` #### Cloudflare Workers We'd _love_ for this to work in cloudflare workers. Unfortunately cloudflare workers have two limitations that prevent `mdx-bundler` from working in that environment: 1. Workers can't run binaries. `bundleMDX` uses `esbuild` (a binary) to bundle your MDX code. 2. Workers can't run `eval` or similar. `getMDXComponent` evaluates the bundled code using `new Function`. One workaround to this is to put your mdx-bundler related code in a different environment and call that environment from within the Cloudflare worker. IMO, this defeats the purpose of using Cloudflare workers. Another potential workaround is to use WASM from within the worker. There is [`esbuild-wasm`](https://esbuild.github.io/getting-started/#install-the-wasm-version) but there are some issues with that package explained at that link. Then there's [`wasm-jseval`](https://github.com/maple3142/wasm-jseval), but I couldn't get that to run code that was output from `mdx-bundler` without error. If someone would like to dig into this, that would be stellar, but unfortunately it's unlikely I'll ever work on it. #### Next.JS esbuild ENOENT esbuild relies on `__dirname` to work out where is executable is, Next.JS and Webpack can sometimes break this and esbuild needs to be told manually where to look. Adding the following code before your `bundleMDX` will point esbuild directly at the correct executable for your platform. ```js import path from 'path' if (process.platform === 'win32') { process.env.ESBUILD_BINARY_PATH = path.join( process.cwd(), 'node_modules', 'esbuild', 'esbuild.exe', ) } else { process.env.ESBUILD_BINARY_PATH = path.join( process.cwd(), 'node_modules', 'esbuild', 'bin', 'esbuild', ) } ``` More information on this issue can be found [in this article](https://www.arcath.net/2021/03/mdx-bundler#esbuild-executable). ## Inspiration As I was rewriting [kentcdodds.com](https://kentcdodds.com) to [remix](https://remix.run), I decided I wanted to keep my blog posts as MDX, but I didn't want to have to compile them all at build time or be required to redeploy every time I fix a typo. So I made this which allows my server to compile on demand. ## Other Solutions There's [next-mdx-remote](https://github.com/hashicorp/next-mdx-remote) but it's more of an mdx-compiler than a bundler (can't bundle your mdx for dependencies). Also it's focused on Next.js whereas this is meta-framework agnostic. ## Issues _Looking to contribute? Look for the [Good First Issue][good-first-issue] label._ ### 🐛 Bugs Please file an issue for bugs, missing documentation, or unexpected behavior. [**See Bugs**][bugs] ### 💡 Feature Requests Please file an issue to suggest new features. Vote on feature requests by adding a 👍. This helps maintainers prioritize what to work on. [**See Feature Requests**][requests] ## Contributors ✨ Thanks goes to these people ([emoji key][emojis]):

_{Kent C. Dodds} 💻 📖 🚇 ⚠️	_benwis 🐛 👀	_{Adam Laycock} 💻 ⚠️ 🤔 👀 📖	_Titus 🤔 👀 💻	_{Christian Murphy} 🤔	_{Pedro Duarte} 📖	_{Erik Rasmussen} 📖
_{Omar Syx} 🐛	_{Gaël Haméon} 📖	_{Gabriel Loiácono} 💻 ⚠️	_{Spencer Miskoviak} 📖	_Casper 💻	_{Apostolos Christodoulou} 📖	_{Yordis Prieto} 💻
_xoumi 💻	_Yasin 💻	_{Mohammed 'Mo' Mulazada} 📖	_{Can Rau} 📖	_{Hosenur Rahaman} 📖	_{Maciek Sitkowski} 📖	_Priyang 💻 📖
_Mosaad 📖	_stefanprobst 💻 ⚠️	_{Vlad Moroz} 💻

This project follows the [all-contributors][all-contributors] specification. Contributions of any kind welcome! ## LICENSE MIT [npm]: https://www.npmjs.com [node]: https://nodejs.org [build-badge]: https://img.shields.io/github/workflow/status/kentcdodds/mdx-bundler/validate?logo=github&style=flat-square [build]: https://github.com/kentcdodds/mdx-bundler/actions?query=workflow%3Avalidate [coverage-badge]: https://img.shields.io/codecov/c/github/kentcdodds/mdx-bundler.svg?style=flat-square [coverage]: https://codecov.io/github/kentcdodds/mdx-bundler [version-badge]: https://img.shields.io/npm/v/mdx-bundler.svg?style=flat-square [package]: https://www.npmjs.com/package/mdx-bundler [downloads-badge]: https://img.shields.io/npm/dm/mdx-bundler.svg?style=flat-square [npmtrends]: https://www.npmtrends.com/mdx-bundler [license-badge]: https://img.shields.io/npm/l/mdx-bundler.svg?style=flat-square [license]: https://github.com/kentcdodds/mdx-bundler/blob/main/LICENSE [prs-badge]: https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square [prs]: https://makeapullrequest.com [coc-badge]: https://img.shields.io/badge/code%20of-conduct-ff69b4.svg?style=flat-square [coc]: https://github.com/kentcdodds/mdx-bundler/blob/main/CODE_OF_CONDUCT.md [emojis]: https://github.com/all-contributors/all-contributors#emoji-key [all-contributors]: https://github.com/all-contributors/all-contributors [all-contributors-badge]: https://img.shields.io/github/all-contributors/kentcdodds/mdx-bundler?color=orange&style=flat-square [bugs]: https://github.com/kentcdodds/mdx-bundler/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+sort%3Acreated-desc+label%3Abug [requests]: https://github.com/kentcdodds/mdx-bundler/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc+label%3Aenhancement [good-first-issue]: https://github.com/kentcdodds/mdx-bundler/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc+label%3Aenhancement+label%3A%22good+first+issue%22 [node-gyp]: https://github.com/nodejs/node-gyp#installation

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mdx-bundler	89,546	1,862	64.7 kB	72	hace 4 meses	MIT