micromark-extension-mdxjs-esm

What is micromark-extension-mdxjs-esm?

The micromark-extension-mdxjs-esm package is an extension for the micromark Markdown parser that adds support for parsing MDX.js (Markdown for the component era). It allows users to use JSX within their Markdown documents, enabling the embedding of React components and other JSX elements.

What are micromark-extension-mdxjs-esm's main functionalities?

Parsing MDX syntax

This feature allows the parsing of MDX syntax within Markdown content. The code sample demonstrates how to use the micromark parser with the mdxjs extension to parse a string containing an MDX component.

import {micromark} from 'micromark';
import {mdxjs} from 'micromark-extension-mdxjs-esm';

const output = micromark('<MyComponent />', {
extensions: [mdxjs()]
});

Support for JSX

This feature enables the use of JSX within Markdown documents. The code sample shows how to parse a Markdown string that includes a JSX component with a prop.

import {micromark} from 'micromark';
import {mdxjs} from 'micromark-extension-mdxjs-esm';

const output = micromark('# Hello, world!\n\n<MyComponent prop1={value} />', {
extensions: [mdxjs()]
});

Other packages similar to micromark-extension-mdxjs-esm

remark-mdx

remark-mdx is a plugin for the remark Markdown processor that adds support for MDX. It is similar to micromark-extension-mdxjs-esm in that it allows for MDX syntax in Markdown files, but it is built on top of the remark ecosystem.

unified

unified is an interface for parsing, transforming, and serializing content through syntax trees and is often used with remark and rehype plugins. While not specific to MDX, it can be used in conjunction with other plugins to achieve similar functionality to micromark-extension-mdxjs-esm.

README

micromark-extension-mdxjs-esm

micromark extension to support MDX.js ESM import/exports.

This package provides the low-level modules for integrating with the micromark tokenizer but has no handling of compiling to HTML: go to a syntax tree instead.

You should probably use this with mdast-util-mdxjs-esm (mdast). Or use micromark-extension-mdxjs and mdast-util-mdx instead, which includes both, to support all of MDX.js. Or, use those through remark-mdx (remark).

Install

npm:

npm install micromark-extension-mdxjs-esm

Use

See mdast-util-mdxjs-esm for an example.

API

syntax(options)

Support ESM imports and exports of MDX.

The export of syntax is a function that can be called with options and returns an extension for the micromark parser (to tokenize import/exports; can be passed in extensions).

options

options.acorn

Acorn parser to use (Acorn, required).

options.acornOptions

Options to pass to acorn (Object, default: {ecmaVersion: 2020, locations: true, sourceType: 'module'}). All fields except for locations can be set.

options.addResult

Whether to add an estree field to mdxjsEsm tokens with results from acorn (boolean, default: false).

Syntax

All valid imports and exports are supported, depending on what the given acorn instance and configuration supports.

When the lowercase strings export or import are found, followed by unicode whitespace (\s), we expect JavaScript. Otherwise, like normal in markdown, we exit and it’ll end up as a paragraph. We continue parsing until we find a line ending followed by a blank line. At that point, we parse with acorn: it if parses, we found our block. Otherwise, if parsing failed at the last character, we assume it’s a blank line in code: we continue on until the next blank line and try again. Otherwise, the acorn error is thrown.

import a from "b"
import * as a from "b"
import {a} from "b"
import {a as b} from "c"
import a, {b as c} from "d"
import a, * as b from "c"
import "a"

export var a = ""
export const a = ""
export let a = ""
export var a, b
export var a = "a", b = "b"
export function a() {}
export class a {}
export var {a} = {}
export var {a: b} = {}
export var [a] = []
export default a = 1
export default function a() {}
export default class a {}
export * from "a"
export * as a from "b"
export {a} from "b"
export {a as b} from "c"
export {default} from "b"
export {default as a, b} from "c"

{/* Blank lines are supported in expressions: */}

export function a() {

  return "b"

}

{/* A blank line must be used after import/exports: this is incorrect! */}

import a from "b"
## Hello, world!

Errors

Could not parse import/exports with acorn: $error

This error occurs if acorn crashes (source: micromark-extension-mdxjs-esm, rule id: acorn). For example:

import 1/1

Unexpected $type in code: only import/exports are supported

This error occurs when a non-ESM construct is found (source: micromark-extension-mdxjs-esm, rule id: non-esm). For example:

export var a = 1
var b

Tokens

An mdxjsEsm token is used to reflect the block of import/exports in markdown.

It includes:

• lineEnding for the \r, \n, and \r\n
• lineEndingBlank for the same characters but when after potential whitespace and another line ending
• whitespace for markdown spaces and tabs in blank lines
• mdxjsEsmData for any character in a line of mdxjsEsm

Related

• micromark/micromark — the smallest commonmark-compliant markdown parser that exists
• micromark/micromark-extension-mdx — support MDX
• micromark/micromark-extension-mdxjs — support MDX.js
• micromark/micromark-extension-mdx-expression — support MDX (or MDX.js) expressions
• micromark/micromark-extension-mdx-jsx — support MDX (or MDX.js) JSX
• micromark/micromark-extension-mdx-md — support misc MDX changes
• syntax-tree/mdast-util-mdx — support MDX (or MDX.js) in mdast

Contribute

See contributing.md in micromark/.github for ways to get started. See support.md 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