mrk.js

🗒️ mrk

The happy little extendable markdown parser

Use it | Try it | Extensions

mrk is an easily extendable markdown parser created for Decent. We needed it for a few reasons:

• We didn't want to have to bring in an npm module or do anything fancy to use it
• We needed to be able to disable features and add new ones easily
• We wanted access to the parsed token stream
• We wanted something small, simple, and easy to extend

How do I use it?

Include mrk.js in your page, or npm install mrkjs: Usage is as follows:

// require('mrk.js') or <script src='mrk.js'></script>

let mark = mrk()
let html = mark('Some _markdown_').html()
console.log(html)

That's it! You can also directly access the parsed token stream by looking at mark(...).tokens, if you're so inclined.

Can I haz Promise?

Yes!!

const mrk = require('mrk.js/async')
const mark = mrk()

mark('Awesome!').then(parsed => {
  console.log('tokens:', parsed.tokens)

  return parsed.html()
}).then(html => {
  console.log('HTML:', html)
})

I want/to remove Feature X!

You can implement/remove it yourself. mrk was designed to be easily extendable:

Removing a feature

mark('Visit http://google.com').html() // Visit <a href='http://google.com'>http://google.com</a>

delete mark.patterns.autolink // See mrk.js for other patterns/features you can remove

mark('Visit http://google.com').html() // Visit http://google.com

Adding a new parse rule

Say we wanted to add ~~strikethrough~~ text, GFM-style:

// Pass `mrk()` extensions to patterns, pairs, or htmlify
const markWithStrikethrough = mrk({
  extendPatterns: {
    strikethroughStart: ({ read, has }) => {
      // If this function returns a truthy value, it will be parsed as a strikethroughStart token
      // See mrk.js for how `read` and `has` work, plus other functions you get access to.

      return read(2) === '~~' // Next 2 characters should be `~~`
        && !has('strikethroughStart', 'strikethroughEnd') // Not already strikethrough!
    },

    strikethroughEnd: ({ read, has }) => {
      return read(2) === '~~' // Next 2 characters should be `~~`
        && has('strikethroughStart', 'strikethroughEnd') // Must have a strikethroughStart before this token
    },
  },

  extendPairs: {
    // If there is a strikethroughStart token on its own without a strikethroughEnd token to be paired
    // to, it will be discarded and parsed as text.
    strikethroughStart: 'strikethroughEnd'
  },

  extendHtmlify: {
    // Declares how to convert these tokens into HTML strings.
    strikethroughStart = () => '<s>',
    strikethroughEnd = () => '</s>'
  }
})

// :tada:
mrk('~~hello~~').html() // => <s>hello</s>

If you end up creating an extension for mrk for your project and it's generic enough, please consider adding it to the list of community extensions for mrk. I'd appreciate it!

License

MIT :tada: