A simple markdown editor with preview, implemented with React.js and TypeScript. This React Component aims to provide a simple Markdown editor with syntax highlighting support. This is based on textarea encapsulation, so it does not depend on any modern code editors such as Acs, CodeMirror, Monaco etc.

Features

• 📑 Indent line or selected text by pressing tab key, with customizable indentation.
• ♻️ Based on textarea encapsulation, does not depend on any modern code editors.
• 🚧 Does not depend on the uiw component library.
• 🚘 Automatic list on new lines.

Quick Start

npm i @uiw/react-md-editor

Using

import React from "react";
import ReactDOM from "react-dom";
import MDEditor from '@uiw/react-md-editor';

export default function App() {
  const [value, setValue] = React.useState("**Hello world!!!**");
  return (
    <div className="container">
      <MDEditor
        value={value}
        onChange={setValue}
      />
      <MDEditor.Markdown source={value} />
    </div>
  );
}

• Demo preview for CodeSandbox
• Demo preview for Github gh-pages
• Demo preview for Gitee gh-pages

Custom Toolbars

import React from "react";
import ReactDOM from "react-dom";
import MDEditor, { commands } from '@uiw/react-md-editor';

const title3: commands.ICommand = {
  name: 'title3',
  keyCommand: 'title3',
  buttonProps: { 'aria-label': 'Insert title3' },
  icon: (
    <svg width="12" height="12" viewBox="0 0 520 520">
      <path fill="currentColor" d="M15.7083333,468 C7.03242448,468 0,462.030833 0,454.666667 L0,421.333333 C0,413.969167 7.03242448,408 15.7083333,408 L361.291667,408 C369.967576,408 377,413.969167 377,421.333333 L377,454.666667 C377,462.030833 369.967576,468 361.291667,468 L15.7083333,468 Z M21.6666667,366 C9.69989583,366 0,359.831861 0,352.222222 L0,317.777778 C0,310.168139 9.69989583,304 21.6666667,304 L498.333333,304 C510.300104,304 520,310.168139 520,317.777778 L520,352.222222 C520,359.831861 510.300104,366 498.333333,366 L21.6666667,366 Z M136.835938,64 L136.835937,126 L107.25,126 L107.25,251 L40.75,251 L40.75,126 L-5.68434189e-14,126 L-5.68434189e-14,64 L136.835938,64 Z M212,64 L212,251 L161.648438,251 L161.648438,64 L212,64 Z M378,64 L378,126 L343.25,126 L343.25,251 L281.75,251 L281.75,126 L238,126 L238,64 L378,64 Z M449.047619,189.550781 L520,189.550781 L520,251 L405,251 L405,64 L449.047619,64 L449.047619,189.550781 Z" />
    </svg>
  ),
  execute: (state: commands.TextState, api: commands.TextApi) => {
    let modifyText = `### ${state.selectedText}\n`;
    if (!state.selectedText) {
      modifyText = `### `;
    }
    api.replaceSelection(modifyText);
  },
};

export default function App() {
  const [value, setValue] = React.useState("**Hello world!!!**");
  return (
    <div className="container">
      <MDEditor
        value="Hello Markdown!"
        commands={[
          commands.bold, commands.hr, commands.italic, commands.divider, commands.codeEdit, commands.codeLive, commands.codePreview, commands.divider,
          commands.fullscreen, 
          // Custom Toolbars
          title3,
        ]}
      />
    </div>
  );
}

Preview Markdown

import React from "react";
import ReactDOM from "react-dom";
import MDEditor from '@uiw/react-md-editor';

export default function App() {
  return (
    <div className="container">
      <MDEditor.Markdown source="Hello Markdown!" />
    </div>
  );
}

Support Custom KaTeX Preview

KaTeX is a fast, easy-to-use JavaScript library for TeX math rendering on the web, We perform math rendering through KaTeX.

The following example is preview in CodeSandbox.

npm install katex

import React from "react";
import ReactDOM from "react-dom";
import MDEditor from '@uiw/react-md-editor';
import katex from 'katex';
import 'katex/dist/katex.css';


const mdKaTeX = `This is to display the 
\`\$\$\c = \\pm\\sqrt{a^2 + b^2}\$\$\`
 in one line

\`\`\`KaTeX
c = \\pm\\sqrt{a^2 + b^2}
\`\`\`
`;

const renderers = {
  inlineCode: ({ children }) => {
    if (/^\$\$(.*)\$\$/.test(children)) {
      const html = katex.renderToString(children.replace(/^\$\$(.*)\$\$/, '$1'), {
        throwOnError: false,
      });
      return <code dangerouslySetInnerHTML={{ __html: html }} />
    }
    return children;
  },
  code: ({ children, language, value }) => {
    if (language.toLocaleLowerCase() === 'katex') {
      const html = katex.renderToString(value, {
        throwOnError: false
      });
      return (
        <pre>
          <code dangerouslySetInnerHTML={{ __html: html }} />
        </pre>
      );
    }
    return children;
  }
}

export default function App() {
  return (
    <MDEditor value={mdKaTeX} previewOptions={{ renderers: renderers }} />
  );
}

Props

• value: string: The Markdown value.
• onChange?: (value: string): Event handler for the onChange event.
• commands?: ICommand[]: An array of ICommand, which, each one, contain a commands property. If no commands are specified, the default will be used. Commands are explained in more details below.
• autoFocus?: number=true: Can be used to make Markdown Editor focus itself on initialization.
• previewOptions?: ReactMarkdown.ReactMarkdownProps: This is reset react-markdown settings.
• textareaProps?: TextareaHTMLAttributes: Set the textarea related props.
• height?: number=200: The height of the editor.
• visiableDragbar?: boolean=true: Show drag and drop tool. Set the height of the editor.
• fullscreen?: boolean=false: Show markdown preview.
• preview?: 'live' | 'edit' | 'preview': Default value live, Show markdown preview.
• maxHeight?: number=1200: Maximum drag height. The visiableDragbar=true value is valid.
• minHeights?: number=100: Minimum drag height. The visiableDragbar=true value is valid.
• tabSize?: number=2: The number of characters to insert when pressing tab key. Default 2 spaces.

Development

npm run watch:types  # Listen create type files.
npm run watch:ts     # Listen compile .tsx files.
npm run doc:dev      # Preview code example.

Other

If you need more features-rich Markdown Editor, you can use @uiwjs/react-markdown-editor

License

Licensed under the MIT License.