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Marked Documentation

Marked instance

By default, Marked stores options and extensions in the global scope. That means changing the options in one script will also change the options in another script since they share the same instance.

If you don't want to mutate global scope, you can create a new instance of Marked to ensure options and extensions are locally scoped.

import { Marked } from 'marked';
const marked = new Marked([options, extension, ...]);
Argument Type Notes
options object The same arguments that can be passed to marked.use

The parse function

import { marked } from 'marked';
marked.parse(markdownString [,options])
Argument Type Notes
markdownString string String of markdown source to be compiled.
options object Hash of options. Can also use marked.use to set global options

Alternative using reference

// Create reference instance
import { marked } from 'marked';

// Set options
marked.use({
  async: true,
  pedantic: false,
  gfm: true,
});

// Compile
console.log(marked.parse(markdownString));

Options

Member Type Default Since Notes
async boolean false 4.1.0 If true, walkTokens functions can be async and marked.parse will return a promise that resolves when all walk tokens functions resolve.
breaks boolean false v0.2.7 If true, add <br> on a single line break (copies GitHub behavior on comments, but not on rendered markdown files). Requires gfm be true.
gfm boolean true v0.2.1 If true, use approved GitHub Flavored Markdown (GFM) specification.
pedantic boolean false v0.2.1 If true, conform to the original markdown.pl as much as possible. Don't fix original markdown bugs or behavior. Turns off and overrides gfm.
renderer object new Renderer() v0.3.0 An object containing functions to render tokens to HTML. See extensibility for more details.
silent boolean false v0.2.7 If true, the parser does not throw any exception or log any warning. Any error will be returned as a string.
tokenizer object new Tokenizer() v1.0.0 An object containing functions to create tokens from markdown. See extensibility for more details.
walkTokens function null v1.1.0 A function which is called for every token. See extensibility for more details.

Known Extensions

Marked can be extended using custom extensions. This is a list of extensions that can be used with marked.use(extension).

Name Package Name Description
Admonition marked-admonition-extension Admonition extension
Base URL marked-base-url Prefix relative urls with a base URL.
Bidi marked-bidi Add Bidirectional text support to the HTML
Custom Heading ID marked-custom-heading-id Specify a custom heading id in headings with the Markdown Extended Syntax # heading {#custom-id}
Emoji marked-emoji Add emoji support like on GitHub
Extended Tables marked-extended-tables Extends the standard Github-Flavored tables to support advanced features: Column Spanning, Row Spanning, Multi-row headers
GFM Heading ID marked-gfm-heading-id Use github-slugger to create the heading IDs and allow a custom prefix.
Highlight marked-highlight Highlight code blocks
Katex Code marked-katex-extension Render katex code
LinkifyIt marked-linkify-it Use linkify-it for urls
Mangle marked-mangle Mangle mailto links with HTML character references
Misskey-flavored Markdown marked-mfm Custom extension for Misskey-flavored Markdown.
Smartypants marked-smartypants Use smartypants to use "smart" typographic punctuation for things like quotes and dashes.
XHTML marked-xhtml Emit self-closing HTML tags for void elements (<br/>, <img/>, etc.) with a "/" as required by XHTML.

Inline Markdown

You can parse inline markdown by running markdown through marked.parseInline.

const blockHtml = marked.parse('**strong** _em_');
console.log(blockHtml); // '<p><strong>strong</strong> <em>em</em></p>'

const inlineHtml = marked.parseInline('**strong** _em_');
console.log(inlineHtml); // '<strong>strong</strong> <em>em</em>'

Highlighting

Use marked-highlight to highlight code blocks.

Workers

To prevent ReDoS attacks you can run marked on a worker and terminate it when parsing takes longer than usual.

Marked can be run in a worker thread on a node server, or a web worker in a browser.

Node Worker Thread

// markedWorker.js

import { marked } from 'marked';
import { parentPort } from 'worker_threads';

parentPort.on('message', (markdownString) => {
  parentPort.postMessage(marked.parse(markdownString));
});
// index.js

import { Worker } from 'worker_threads';
const markedWorker = new Worker('./markedWorker.js');

const markedTimeout = setTimeout(() => {
  markedWorker.terminate();
  throw new Error('Marked took too long!');
}, timeoutLimit);

markedWorker.on('message', (html) => {
  clearTimeout(markedTimeout);
  console.log(html);
  markedWorker.terminate();
});

markedWorker.postMessage(markdownString);

Web Worker

NOTE: Web Workers send the payload from postMessage in an object with the payload in a .data property

// markedWorker.js

importScripts('path/to/marked.min.js');

onmessage = (e) => {
  const markdownString = e.data
  postMessage(marked.parse(markdownString));
};
// script.js

const markedWorker = new Worker('./markedWorker.js');

const markedTimeout = setTimeout(() => {
  markedWorker.terminate();
  throw new Error('Marked took too long!');
}, timeoutLimit);

markedWorker.onmessage = (e) => {
  clearTimeout(markedTimeout);
  const html = e.data;
  console.log(html);
  markedWorker.terminate();
};

markedWorker.postMessage(markdownString);

CLI Extensions

You can use extensions in the CLI by creating a new CLI that imports marked and the marked binary.

// file: myMarked
#!/usr/bin/node

import { marked } from 'marked';
import customHeadingId from 'marked-custom-heading-id';

marked.use(customHeadingId());

import 'marked/bin/marked';
$ ./myMarked -s "# heading {#custom-id}"
<h1 id="custom-id">heading</h1>