MarkdownViewer

Release notes

Thoughtful defaults, ordinary CSS.

Native controls
Source ownership

--dvy-brand: #282724;

Usage

import { MarkdownViewer } from "@devvy-ui/react";

<MarkdownViewer source={'## Release notes\n\n**Build** with ordinary CSS.'} />

API reference

Native HTML attributes, className, style and a forwarded ref are supported. Component-specific props:

Prop	Type	Default	Description
source	string	required	Markdown text.
headingLevel	2–6	2	Heading level for a single # marker.

Source ownership

Run npx @devvy-ui/cli init once in your React project, then add the source:

npx @devvy-ui/cli add markdown-viewer

Make the source yours.

Start from the canonical implementation used by the package and registry. Change the code, keep the MIT notice, and build the behavior your project needs.

MarkdownViewer.tsxREACT / TSX

import { createElement, forwardRef, type HTMLAttributes, type ReactNode } from 'react';
import { safeURL } from '../lib/widgets';
export interface MarkdownViewerProps extends Omit<HTMLAttributes<HTMLDivElement>, 'children'> {
  source: string;
  headingLevel?: 2 | 3 | 4 | 5 | 6;
}
function inline(text: string): ReactNode[] {
  const pattern = /\[([^\]]+)\]\(([^)]+)\)|\*\*([^*]+)\*\*|_([^_]+)_|`([^`]+)`/g;
  const nodes: ReactNode[] = [];
  let last = 0;
  for (const match of text.matchAll(pattern)) {
    const at = match.index!;
    nodes.push(text.slice(last, at));
    const key = String(at);
    if (match[1]) {
      const href = safeURL(match[2]);
      nodes.push(
        href ? (
          <a key={key} href={href}>
            {match[1]}
          </a>
        ) : (
          <span key={key}>{match[1]}</span>
        ),
      );
    } else if (match[3]) nodes.push(<strong key={key}>{match[3]}</strong>);
    else if (match[4]) nodes.push(<em key={key}>{match[4]}</em>);
    else nodes.push(<code key={key}>{match[5]}</code>);
    last = at + match[0].length;
  }
  nodes.push(text.slice(last));
  return nodes;
}
/** A documented safe Markdown subset; raw HTML is always text. */
export const MarkdownViewer = forwardRef<HTMLDivElement, MarkdownViewerProps>(
  function MarkdownViewer({ source, headingLevel = 2, className, ...props }, ref) {
    const lines = source.replace(/\r\n/g, '\n').split('\n'),
      blocks: ReactNode[] = [];
    for (let i = 0; i < lines.length; i++) {
      const line = lines[i];
      if (line.startsWith('```')) {
        const code: string[] = [];
        while (++i < lines.length && !lines[i].startsWith('```')) code.push(lines[i]);
        blocks.push(
          <pre key={i} role="region" aria-label={'Code block ' + (blocks.length + 1)} tabIndex={0}>
            <code>{code.join('\n')}</code>
          </pre>,
        );
        continue;
      }
      const heading = /^(#{1,6})\s+(.+)$/.exec(line);
      if (heading) {
        blocks.push(
          createElement(
            'h' + Math.min(6, headingLevel + heading[1].length - 1),
            { key: i },
            inline(heading[2]),
          ),
        );
        continue;
      }
      if (/^[-*] /.test(line)) {
        const items: ReactNode[] = [];
        while (i < lines.length && /^[-*] /.test(lines[i])) {
          items.push(<li key={i}>{inline(lines[i].slice(2))}</li>);
          i++;
        }
        i--;
        blocks.push(<ul key={i}>{items}</ul>);
        continue;
      }
      if (line.trim()) blocks.push(<p key={i}>{inline(line)}</p>);
    }
    return (
      <div {...props} ref={ref} className={['dvy-markdown', className].filter(Boolean).join(' ')}>
        {blocks}
      </div>
    );
  },
);

Edit your own copy. Downloaded source uses your changes; the component preview above uses the shipped version. Run the source installer first to include shared helpers.

Interactive preview

Release notes

Usage

API reference

Accessibility & behavior

Platform Behavior & Guidelines

Source ownership

Make the source yours.