marky-markdown

marky-markdown is a markdown parser, written in NodeJS, that aims for parity with GitHub-style markdown. It is built on top of markdown-it, a CommonMark markdown parser. You can use marky-markdown:

• programmatically in NodeJS
• in your terminal
• in the browser *does not yet support syntax highlighting

marky-markdown is the thing that parses package READMEs on http://www.npmjs.com. If you see a markdown parsing bug there, file an issue here!

Installation

npm install marky-markdown --save

Programmatic Usage

marky-markdown exports a single function. For basic use, that function takes a single argument: a string to convert.

var marky = require("marky-markdown")
marky("# hello, I'm markdown").html()

Options

The exported function takes an optional options object as its second argument:

marky("some trusted string", {sanitize: false}).html()

The default options are as follows:

{
  sanitize: true,               // remove script tags and stuff
  linkify: true,                // turn orphan URLs into hyperlinks
  highlightSyntax: true,        // run highlights on fenced code blocks
  prefixHeadingIds: true,       // prevent DOM id collisions
  enableHeadingLinkIcons: true, // render icons inside generated section links
  serveImagesWithCDN: false,    // use npm's CDN to proxy images over HTTPS
  debug: false,                 // console.log() all the things
  package: null                 // npm package metadata
}

Command-line Usage

You can use marky-markdown to parse markdown files in the shell. The easiest way to do this is to install globally:

npm i -g marky-markdown
marky-markdown some.md > some.html

In the Browser

This module mostly works in the browser, with the exception of the highlights module.

You can require('marky-markdown') in scripts you browserify yourself, or just use the standalone file in [dist/marky-markdown.js].

Here is an example using HTML5 to render text inside <marky-markdown> tags.

<script src="marky-markdown.js"></script>

<marky-markdown>**Here** _is_ some [Markdown](https://github.com/)</marky-markdown>

<script>
  for (el of document.getElementsByTagName('marky-markdown')) {
    el.innerHTML = markyMarkdown(el.innerText, {highlightSyntax: false}).html()
  }
</script>

Note: Usage with webpack requires that your webpack.config.js configure a loader (such as json-loader) for .json files.

Tests

npm install
npm test

What it does

• Parses markdown with markdown-it, a fast and commonmark-compliant parser.
• Removes broken and malicious user input with sanitize-html
• Applies syntax highlighting to GitHub-flavored code blocks using the highlights library from Atom.
• Uses cheerio to perform various feats of DOM manipulation.
• Converts :emoji:-style shortcuts to unicode emojis.
• Converts headings (h1, h2, etc) into anchored hyperlinks.
• Converts relative GitHub links to their absolute equivalents.
• Converts relative GitHub images sources to their GitHub raw equivalents.
• Converts insecure Gravatar URLs to HTTPS.
• Converts list items with leading [ ] and [x] into GitHub-style task lists
• Wraps embedded YouTube videos so they can be styled.
• Parses and sanitizes package.description as markdown.
• Applies CSS classes to redundant content that closely matches npm package name and description.
• Applies CSS classes to badge images, so we can do something interesting with them one day.

cheerio "middleware"

marky-markdown always returns the generated HTML document as a cheerio DOM object that can be queried using a familiar jQuery syntax:

var $ = marky("![cat](cat.png)")
$("img").length
// => 1
$("img").attr("src")
// => "cat.png"

npm packages

Pass in an npm package object to do stuff like rewriting relative URLs to their absolute equivalent on GitHub, normalizing package metadata with redundant readme content, etc

var package = {
  name: "foo",
  description: "foo is a thing",
  repository: {
    type: "git",
    url: "https://github.com/kung/foo"
  }
}

marky(
  "# hello, I am the foo readme",
  {package: package}
).html()

Dependencies

• cheerio: Tiny, fast, and elegant implementation of core jQuery designed specifically for the server
• github-slugger: Generate a slug just like GitHub does for markdown headings
• github-url-to-object: Extract user, repo, and other interesting properties from GitHub URLs
• highlights: Syntax highlighter
• highlights-tokens: A list of the language tokens used by the Atom.app highlights syntax highlighter
• lodash: A utility library delivering consistency, customization, performance, & extras.
• markdown-it: Markdown-it - modern pluggable markdown parser.
• markdown-it-emoji: Markdown-it-emoji extension for Markdown-it that parses markdown emoji syntax to unicode.
• markdown-it-expand-tabs: Replace leading tabs with spaces in fenced code blocks
• markdown-it-lazy-headers: Lazy ATX headers plugin for markdown-it
• markdown-it-task-lists: Render GitHub-style task lists
• property-ttl: Save memory by nulling out a property after ttl if it has not been accessed
• sanitize-html: Clean up user-submitted HTML, preserving whitelisted elements and whitelisted attributes on a per-element basis
• similarity: How similar are these two strings?

Extra syntax highlighting, in addition to what comes with highlights:

• atom-language-diff: Diff/patch files
• atom-language-nginx: NGINX configuration files
• language-dart: Dart language
• language-erlang: Erlang language
• language-glsl: OpenGL Shading Language files
• language-haxe: Haxe language
• language-ini: .ini configuration files
• language-rust: Rust language
• language-stylus: Stylus CSS preprocessor

License

ISC