remark

What is remark?

The remark npm package is a powerful, extensible Markdown processor built on the unified collective ecosystem. It allows for parsing, transforming, and compiling Markdown content with a focus on syntax trees. Remark can be used for a variety of tasks such as linting Markdown, transforming the syntax for different purposes, or extracting metadata from documents.

What are remark's main functionalities?

Parsing Markdown to Syntax Trees

This feature allows users to parse Markdown content into an abstract syntax tree (AST), enabling programmatic analysis and manipulation of the content.

const remark = require('remark');
const markdown = 'Some **Markdown** text.';
remark().parse(markdown);

Transforming Syntax Trees

With this feature, users can transform the syntax tree generated from Markdown content. For example, converting the tree to HTML by using the remark-html plugin.

const remark = require('remark');
const html = require('remark-html');
const markdown = 'Some **Markdown** text.';
remark().use(html).processSync(markdown).toString();

Linting Markdown

This feature enables users to lint their Markdown content for style and syntax issues, ensuring consistency and quality in their Markdown files.

const remark = require('remark');
const recommended = require('remark-preset-lint-recommended');
const report = require('vfile-reporter');

remark().use(recommended).process('_Emphasis_ and **importance**', (err, file) => {
  console.error(report(err || file));
});

Other packages similar to remark

markdown-it

markdown-it is a fast and extensible Markdown parser that can render HTML. It is similar to remark in its extensibility but focuses more on speed and adherence to the CommonMark specification without an emphasis on abstract syntax trees.

showdown

showdown is another Markdown to HTML converter that can run both in the browser and on the server. Unlike remark, which is built around a plugin ecosystem and AST manipulation, showdown focuses on configurability and extension through a different type of extension mechanism.

marked

marked is a low-level Markdown compiler for parsing Markdown without caching or blocking for files. It is designed for speed and is simpler in scope compared to remark, which offers a broader range of processing capabilities through its plugins and unified ecosystem.

README

remark

A full-featured markdown parser and compiler, written in javascript. Built for speed.

Fork of marked. Will pull all commits from master. Pull requests welcome.

Install

npm install marked --save

Usage

Minimal usage:

console.log(marked('I am using __markdown__.'));
// Outputs: <p>I am using <strong>markdown</strong>.</p>

Example using all options:

// Set default options except highlight which has no default
marked.setOptions({
  gfm: true,
  highlight: function (code, lang, callback) {
    pygmentize({ lang: lang, format: 'html' }, code, function (err, result) {
      if (err) return callback(err);
      callback(null, result.toString());
    });
  },
  tables: true,
  breaks: false,
  pedantic: false,
  sanitize: true,
  smartLists: true,
  smartypants: false,
  langPrefix: 'lang-'
});

// Using async version of marked
marked('I am using __markdown__.', function (err, content) {
  if (err) throw err;
  console.log(content);
});

marked(markdownString, [options], [callback])

markdownString

Type: String

String of markdown source to be compiled.

options

Type: Object

Hash of options. Can also be set using the marked.setOptions method as seen above.

callback

Type: Function

Function called when the markdownString has been fully parsed when using async highlighting. If the options argument is omitted, this can be used as the second argument as seen above:

Options

gfm

Type: Boolean Default: true

Enable GitHub flavored markdown.

highlight

Type: Function

A function to highlight code blocks. The function takes three arguments: code, lang, and callback. The above example uses async highlighting with node-pygementize-bundled, and here is a synchronous example using highlight.js which doesn't require the callback argument:

marked.setOptions({
  highlight: function (code, lang) {
    return hljs.highlightAuto(lang, code).value;
  }
});

highlight arguments

code

Type: String

The section of code to pass to the highlighter.

lang

Type: String

The programming language specified in the code block.

callback

Type: String

The callback function to call when using an async highlighter.

tables

Type: Boolean Default: true

Enable GFM tables. This option requires the gfm option to be true.

breaks

Type: Boolean Default: false

Enable GFM line breaks. This option requires the gfm option to be true.

pedantic

Type: Boolean Default: false

Conform to obscure parts of markdown.pl as much as possible. Don't fix any of the original markdown bugs or poor behavior.

sanitize

Type: Boolean Default: false

Sanitize the output. Ignore any HTML that has been input.

smartLists

Type: Boolean Default: true

Use smarter list behavior than the original markdown. May eventually be default with the old behavior moved into pedantic.

smartypants

Type: Boolean Default: false

Use "smart" typograhic punctuation for things like quotes and dashes.

langPrefix

Type: String Default: lang-

Set the prefix for code block classes.

headerPrefix

Type: String Default: ``

Set the prefix for header IDs.

Access to lexer and parser

You also have direct access to the lexer and parser if you so desire.

var tokens = marked.lexer(text, options);
console.log(marked.parser(tokens));

var lexer = new marked.Lexer(options);
var tokens = lexer.lex(text);
console.log(tokens);
console.log(lexer.rules);

CLI

$ marked -o hello.html
hello world
^D
$ cat hello.html
<p>hello world</p>

Benchmarks

node v0.4.x

$ node test --bench
marked completed in 12071ms.
showdown (reuse converter) completed in 27387ms.
showdown (new converter) completed in 75617ms.
markdown-js completed in 70069ms.

node v0.6.x

$ node test --bench
marked completed in 6448ms.
marked (gfm) completed in 7357ms.
marked (pedantic) completed in 6092ms.
discount completed in 7314ms.
showdown (reuse converter) completed in 16018ms.
showdown (new converter) completed in 18234ms.
markdown-js completed in 24270ms.

Marked is now faster than Discount, which is written in C.

For those feeling skeptical: These benchmarks run the entire markdown test suite 1000 times. The test suite tests every feature. It doesn't cater to specific aspects.

node v0.8.x

$ node test --bench
marked completed in 3411ms.
marked (gfm) completed in 3727ms.
marked (pedantic) completed in 3201ms.
robotskirt completed in 808ms.
showdown (reuse converter) completed in 11954ms.
showdown (new converter) completed in 17774ms.
markdown-js completed in 17191ms.

Another Javascript Markdown Parser

The point of marked was to create a markdown compiler where it was possible to frequently parse huge chunks of markdown without having to worry about caching the compiled output somehow...or blocking for an unnecesarily long time.

marked is very concise and still implements all markdown features. It is also now fully compatible with the client-side.

marked more or less passes the official markdown test suite in its entirety. This is important because a surprising number of markdown compilers cannot pass more than a few tests. It was very difficult to get marked as compliant as it is. It could have cut corners in several areas for the sake of performance, but did not in order to be exactly what you expect in terms of a markdown rendering. In fact, this is why marked could be considered at a disadvantage in the benchmarks above.

Along with implementing every markdown feature, marked also implements GFM features.

$ node
> require('marked').lexer('> i am using marked.')
[ { type: 'blockquote_start' },
  { type: 'paragraph',
    text: 'i am using marked.' },
  { type: 'blockquote_end' },
  links: {} ]

Running Tests & Contributing

If you want to submit a pull request, make sure your changes pass the test suite. If you're adding a new feature, be sure to add your own test.

The marked test suite is set up slightly strangely: test/new is for all tests that are not part of the original markdown.pl test suite (this is where your test should go if you make one). test/original is only for the original markdown.pl tests. test/tests houses both types of tests after they have been combined and moved/generated by running node test --fix or marked --test --fix.

In other words, if you have a test to add, add it to test/new/ and then regenerate the tests with node test --fix. Commit the result. If your test uses a certain feature, for example, maybe it assumes GFM is not enabled, you can add .nogfm to the filename. So, my-test.text becomes my-test.nogfm.text. You can do this with any marked option. Say you want line breaks and smartypants enabled, your filename should be: my-test.breaks.smartypants.text.

To run the tests:

cd marked/
node test

Contribution and License Agreement

If you contribute code to marked, you are implicitly allowing your code to be distributed under the MIT license. You are also implicitly verifying that all code is your original work. </legalese>

License

Copyright (c) 2011-2013, Christopher Jeffrey. (MIT License)

See LICENSE for more info.