react-markdown

What is react-markdown?

The react-markdown npm package is a markdown renderer for React applications. It allows you to take Markdown content and render it as React components. This is useful for content-driven applications, such as blogs or documentation sites, where you want to allow content creators to write in Markdown and then display that content within your React application.

What are react-markdown's main functionalities?

Rendering Markdown

This feature allows you to render standard Markdown text as React components. The example code shows how to import the ReactMarkdown component and use it to render a simple piece of Markdown text.

import React from 'react';
import ReactMarkdown from 'react-markdown';

const markdown = '# Hello, *world*!';

function App() {
  return <ReactMarkdown>{markdown}</ReactMarkdown>;
}

export default App;

Custom Renderers

This feature allows you to define custom renderers for different Markdown elements. In the example, a custom renderer is provided for 'h1' elements, which renders them with a blue color.

import React from 'react';
import ReactMarkdown from 'react-markdown';

const markdown = '# Hello, *world*!';

function HeadingRenderer(props) {
  return <h1 style={{ color: 'blue' }}>{props.children}</h1>;
}

function App() {
  return (
    <ReactMarkdown
      components={{
        h1: HeadingRenderer
      }}
    >
      {markdown}
    </ReactMarkdown>
  );
}

export default App;

Inline HTML and Skip HTML

This feature allows you to include or exclude inline HTML within your Markdown content. The example code demonstrates how to skip rendering inline HTML by using the 'skipHtml' prop.

import React from 'react';
import ReactMarkdown from 'react-markdown';

const markdown = 'This is a paragraph with <span style="color: red;">inline HTML</span>.';

function App() {
  return (
    <ReactMarkdown skipHtml>
      {markdown}
    </ReactMarkdown>
  );
}

export default App;

Plugins

This feature allows you to extend the functionality of react-markdown with plugins. The example code shows how to use the 'remark-gfm' plugin to add support for GitHub Flavored Markdown (GFM) task lists.

import React from 'react';
import ReactMarkdown from 'react-markdown';
import gfm from 'remark-gfm';

const markdown = 'This supports GitHub Flavored Markdown (GFM)\n\n- [ ] todo\n- [x] done';

function App() {
  return <ReactMarkdown remarkPlugins={[gfm]}>{markdown}</ReactMarkdown>;
}

export default App;

Other packages similar to react-markdown

marked

Marked is a low-level markdown compiler for parsing markdown without caching or blocking for long periods of time. It is less React-specific than react-markdown and requires additional work to integrate with React.

remarkable

Remarkable is a highly configurable markdown parser and compiler. It offers similar functionality to react-markdown but is not designed specifically for React and does not render React components out of the box.

markdown-to-jsx

markdown-to-jsx is another React component that lets you render Markdown as React components. It is similar to react-markdown but offers a simpler API with less configurability, which might be preferable for simpler use cases.

README

react-markdown

Renders Markdown as pure React components.

Demo available at https://rexxars.github.io/react-markdown/

---

react-markdown is proudly sponsored by

Sanity: The Headless CMS Construction Kit

---

Installing

npm install --save react-markdown

Basic usage

const React = require('react')
const ReactDOM = require('react-dom')
const ReactMarkdown = require('react-markdown')

const input = '# This is a header\n\nAnd this is a paragraph'

ReactDOM.render(<ReactMarkdown source={input} />, document.getElementById('container'))

Upgrading to 4.0

Should be straightforward. You might need to alter you code slightly if you:

• Are using allowedTypes (add text to the list)
• Rely on there being a container <div> without a class name around your rendered markdown
• Have implemented a custom text renderer

See CHANGELOG for more details.

Notes

If you don't need to render HTML, this component does not use dangerouslySetInnerHTML at all - this is a Good Thing™.

Options

• source or children - string The Markdown source to parse (required)
• className - string Class name of the container element. If none is passed, a container will not be rendered.
• escapeHtml - boolean Setting to false will cause HTML to be rendered (see notes below about proper HTML support). Be aware that setting this to false might cause security issues if the input is user-generated. Use at your own risk. (default: true).
• skipHtml - boolean Setting to true will skip inlined and blocks of HTML (default: false).
• sourcePos - boolean Setting to true will add data-sourcepos attributes to all elements, indicating where in the markdown source they were rendered from (default: false).
• rawSourcePos - boolean Setting to true will pass a sourcePosition property to all renderers with structured source position information (default: false).
• includeNodeIndex - boolean Setting to true will pass index and parentChildCount props to all renderers (default: false).
• allowedTypes - array Defines which types of nodes should be allowed (rendered). (default: all types).
• disallowedTypes - array Defines which types of nodes should be disallowed (not rendered). (default: none).
• unwrapDisallowed - boolean Setting to true will try to extract/unwrap the children of disallowed nodes. For instance, if disallowing Strong, the default behaviour is to simply skip the text within the strong altogether, while the behaviour some might want is to simply have the text returned without the strong wrapping it. (default: false)
• allowNode - function Function execute if in order to determine if the node should be allowed. Ran prior to checking allowedTypes/disallowedTypes. Returning a truthy value will allow the node to be included. Note that if this function returns true and the type is not in allowedTypes (or specified as a disallowedType), it won't be included. The function will receive three arguments argument (node, index, parent), where node contains different properties depending on the node type.
• linkTarget - function|string Sets the default target attribute for links. If a function is provided, it will be called with url, text, and title and should return a string (e.g. _blank for a new tab). Default is undefined (no target attribute).
• transformLinkUri - function|null Function that gets called for each encountered link with a single argument - uri. The returned value is used in place of the original. The default link URI transformer acts as an XSS-filter, neutralizing things like javascript:, vbscript: and file: protocols. If you specify a custom function, this default filter won't be called, but you can access it as require('react-markdown').uriTransformer. If you want to disable the default transformer, pass null to this option.
• transformImageUri - function|null Function that gets called for each encountered image with a single argument - uri. The returned value is used in place of the original.
• renderers - object An object where the keys represent the node type and the value is a React component. The object is merged with the default renderers. The props passed to the component varies based on the type of node.
• plugins - array An array of unified/remark parser plugins. If you need to pass options to the plugin, pass an array with two elements, the first being the plugin and the second being the options - for instance: {plugins: [[require('remark-shortcodes'), {your: 'options'}]]. (default: []) Note that not all plugins can be used.
• parserOptions - object An object containing options to pass to remark-parse.

Parsing HTML

If you are in a trusted environment and want to parse and render HTML, you will want to use the html-parser plugin. For a default configuration, import react-markdown/with-html instead of the default:

const ReactMarkdown = require('react-markdown/with-html')

const markdown = `
This block of Markdown contains <a href="https://en.wikipedia.org/wiki/HTML">HTML</a>, and will require the <code>html-parser</code> AST plugin to be loaded, in addition to setting the <code class="prop">escapeHtml</code> property to false.
`

<ReactMarkdown
  source={markdown}
  escapeHtml={false}
/>

If you want to specify options for the HTML parsing step, you can instead import the HTML parser plugin directly:

const ReactMarkdown = require('react-markdown')
const htmlParser = require('react-markdown/plugins/html-parser')

// See https://github.com/aknuds1/html-to-react#with-custom-processing-instructions
// for more info on the processing instructions
const parseHtml = htmlParser({
  isValidNode: node => node.type !== 'script',
  processingInstructions: [/* ... */]
})

<ReactMarkdown
  source={markdown}
  escapeHtml={false}
  astPlugins={[parseHtml]}
/>

Node types

The node types available are the following, and applies to both renderers and allowedTypes/disallowedTypes:

• root - Root container element that contains the rendered markdown
• text - Text rendered inside of other elements, such as paragraphs
• break - Hard-break (<br>)
• paragraph - Paragraph (<p>)
• emphasis - Emphasis (<em>)
• strong - Strong/bold (<strong>)
• thematicBreak - Horizontal rule / thematic break (<hr>)
• blockquote - Block quote (<blockquote>)
• delete - Deleted/strike-through (<del>)
• link - Link (<a>)
• image - Image (<img>)
• linkReference - Link (through a reference) (<a>)
• imageReference - Image (through a reference) (<img>)
• table - Table (<table>)
• tableHead - Table head (<thead>)
• tableBody - Table body (<tbody>)
• tableRow - Table row (<tr>)
• tableCell - Table cell (<td>/<th>)
• list - List (<ul>/<ol>)
• listItem - List item (<li>)
• definition - Definition (not rendered by default)
• heading - Heading (<h1>-<h6>)
• inlineCode - Inline code (<code>)
• code - Block of code (<pre><code>)
• html - HTML node (Best-effort rendering)
• virtualHtml - When not using the HTML parser plugin, a cheap and dirty approach to supporting simple HTML elements without a complete parser.
• parsedHtml - When using the HTML parser plugin, HTML parsed to a React element.

Note: Disallowing a node will also prevent the rendering of any children of that node, unless the unwrapDisallowed option is set to true. E.g., disallowing a paragraph will not render its children text nodes.

Developing

git clone [e-mail]:rexxars/react-markdown.git
cd react-markdown
npm install
npm test

License

MIT © Espen Hovlandsdal

Changelog

4.1.0 - 2019-06-24

Added

• Add prop parserOptions to specify options for remark-parse (Kelvin Chan)