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.
• 😻 GitHub flavored markdown support.
• 🌒 Support dark-mode/night-mode @v3.11.0+.
• 💡 Support next.js, Use examples in next.js.

Quick Start

npm i @uiw/react-md-editor

Using

import React from "react";
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} style={{ whiteSpace: 'pre-wrap' }} />
    </div>
  );
}

Special Markdown syntax

Supports for CSS Style

Use HTML comments <!--rehype:xxx--> to let Markdown support style customization.

## Title
<!--rehype:style=display: flex; height: 230px; align-items: center; justify-content: center; font-size: 38px;-->

Markdown Supports **Style**<!--rehype:style=color: red;-->

Ignore content display via HTML comments

Shown in GitHub readme, excluded in HTML.

# Hello World

<!--rehype:ignore:start-->Hello World<!--rehype:ignore:end-->

Good!

Output:

<h1>Hello World</h1>

<p>Good!</p>

Security

Please note markdown needs to be sanitized if you do not completely trust your authors. Otherwise, your app is vulnerable to XSS. This can be achieved by adding rehype-sanitize as a plugin.

import React from "react";
import MDEditor from '@uiw/react-md-editor';
import rehypeSanitize from "rehype-sanitize";

export default function App() {
  const [value, setValue] = React.useState(`**Hello world!!!** <IFRAME SRC=\"javascript:javascript:alert(window.origin);\"></IFRAME>`);
  return (
    <div className="container">
      <MDEditor
        value={value}
        onChange={setValue}
        previewOptions={{
          rehypePlugins: [[rehypeSanitize]],
        }}
      />
    </div>
  );
}

Custom Toolbars

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

const title3 = {
  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, api) => {
    let modifyText = `### ${state.selectedText}\n`;
    if (!state.selectedText) {
      modifyText = `### `;
    }
    api.replaceSelection(modifyText);
  },
};

const title2 = {
  name: 'title2',
  keyCommand: 'title2',
  render: (command, disabled, executeCommand) => {
    return (
      <button 
        aria-label="Insert title2"
        disabled={disabled}
        onClick={(evn) => {
          // evn.stopPropagation();
          executeCommand(command, command.groupName)
        }}
      >
        <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>
      </button>
    )
  },
  execute: (state, api) => {
    let modifyText = `## ${state.selectedText}\n`;
    if (!state.selectedText) {
      modifyText = `## `;
    }
    api.replaceSelection(modifyText);
  },
}

export default function App() {
  const [value, setValue] = React.useState("Hello Markdown! `Tab` key uses default behavior");
  return (
    <div className="container">
      <MDEditor
        value={value}
        onChange={setValue}
        commands={[
          // Custom Toolbars
          title3, title2,
          commands.group([commands.title1, commands.title2, commands.title3, commands.title4, commands.title5, commands.title6], {
            name: 'title',
            groupName: 'title',
            buttonProps: { 'aria-label': 'Insert title'}
          }),
          commands.divider,
          commands.group([], {
            name: 'update',
            groupName: 'update',
            icon: (
              <svg viewBox="0 0 1024 1024" width="12" height="12">
                <path fill="currentColor" d="M716.8 921.6a51.2 51.2 0 1 1 0 102.4H307.2a51.2 51.2 0 1 1 0-102.4h409.6zM475.8016 382.1568a51.2 51.2 0 0 1 72.3968 0l144.8448 144.8448a51.2 51.2 0 0 1-72.448 72.3968L563.2 541.952V768a51.2 51.2 0 0 1-45.2096 50.8416L512 819.2a51.2 51.2 0 0 1-51.2-51.2v-226.048l-57.3952 57.4464a51.2 51.2 0 0 1-67.584 4.2496l-4.864-4.2496a51.2 51.2 0 0 1 0-72.3968zM512 0c138.6496 0 253.4912 102.144 277.1456 236.288l10.752 0.3072C924.928 242.688 1024 348.0576 1024 476.5696 1024 608.9728 918.8352 716.8 788.48 716.8a51.2 51.2 0 1 1 0-102.4l8.3968-0.256C866.2016 609.6384 921.6 550.0416 921.6 476.5696c0-76.4416-59.904-137.8816-133.12-137.8816h-97.28v-51.2C691.2 184.9856 610.6624 102.4 512 102.4S332.8 184.9856 332.8 287.488v51.2H235.52c-73.216 0-133.12 61.44-133.12 137.8816C102.4 552.96 162.304 614.4 235.52 614.4l5.9904 0.3584A51.2 51.2 0 0 1 235.52 716.8C105.1648 716.8 0 608.9728 0 476.5696c0-132.1984 104.8064-239.872 234.8544-240.2816C258.5088 102.144 373.3504 0 512 0z" />
              </svg>
            ),
            children: ({ close, execute, getState, textApi }) => {
              return (
                <div style={{ width: 120, padding: 10 }}>
                  <div>My Custom Toolbar</div>
                  <button type="button" onClick={() => console.log('> execute: >>>>>', getState())}>State</button>
                  <button type="button" onClick={() => close()}>Close</button>
                  <button type="button" onClick={() => execute()}>Execute</button>
                </div>
              );
            },
            execute: (state, api)  => {
              console.log('>>>>>>update>>>>>', state)
            },
            buttonProps: { 'aria-label': 'Insert title'}
          }),
        ]}
      />
    </div>
  );
}

Customize the toolbar with commands and extraCommands props.

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

export default function App() {
  const [value, setValue] = React.useState("Hello Markdown! `Tab` key uses default behavior");
  return (
    <div className="container">
      <MDEditor
        value={value}
        onChange={setValue}
        preview="edit"
        commands={[
          commands.codeEdit, commands.codePreview
        ]}
        extraCommands={[
          commands.group([commands.title1, commands.title2, commands.title3, commands.title4, commands.title5, commands.title6], {
            name: 'title',
            groupName: 'title',
            buttonProps: { 'aria-label': 'Insert title'}
          }),
          commands.divider,
          commands.group([], {
            name: 'update',
            groupName: 'update',
            icon: (
              <svg viewBox="0 0 1024 1024" width="12" height="12">
                <path fill="currentColor" d="M716.8 921.6a51.2 51.2 0 1 1 0 102.4H307.2a51.2 51.2 0 1 1 0-102.4h409.6zM475.8016 382.1568a51.2 51.2 0 0 1 72.3968 0l144.8448 144.8448a51.2 51.2 0 0 1-72.448 72.3968L563.2 541.952V768a51.2 51.2 0 0 1-45.2096 50.8416L512 819.2a51.2 51.2 0 0 1-51.2-51.2v-226.048l-57.3952 57.4464a51.2 51.2 0 0 1-67.584 4.2496l-4.864-4.2496a51.2 51.2 0 0 1 0-72.3968zM512 0c138.6496 0 253.4912 102.144 277.1456 236.288l10.752 0.3072C924.928 242.688 1024 348.0576 1024 476.5696 1024 608.9728 918.8352 716.8 788.48 716.8a51.2 51.2 0 1 1 0-102.4l8.3968-0.256C866.2016 609.6384 921.6 550.0416 921.6 476.5696c0-76.4416-59.904-137.8816-133.12-137.8816h-97.28v-51.2C691.2 184.9856 610.6624 102.4 512 102.4S332.8 184.9856 332.8 287.488v51.2H235.52c-73.216 0-133.12 61.44-133.12 137.8816C102.4 552.96 162.304 614.4 235.52 614.4l5.9904 0.3584A51.2 51.2 0 0 1 235.52 716.8C105.1648 716.8 0 608.9728 0 476.5696c0-132.1984 104.8064-239.872 234.8544-240.2816C258.5088 102.144 373.3504 0 512 0z" />
              </svg>
            ),
            children: ({ close, execute, getState, textApi }) => {
              return (
                <div style={{ width: 120, padding: 10 }}>
                  <div>My Custom Toolbar</div>
                  <button type="button" onClick={() => console.log('> execute: >>>>>', getState())}>State</button>
                  <button type="button" onClick={() => close()}>Close</button>
                  <button type="button" onClick={() => execute()}>Execute</button>
                </div>
              );
            },
            execute: (state, api)  => {
              console.log('>>>>>>update>>>>>', state)
            },
            buttonProps: { 'aria-label': 'Insert title'}
          }),
          commands.divider, commands.fullscreen
        ]}
      />
    </div>
  );
}

re-render toolbar element.

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

export default function App() {
  const [value, setValue] = React.useState("Hello Markdown! `Tab` key uses default behavior");
  return (
    <div className="container">
      <MDEditor
        value={value}
        onChange={setValue}
        preview="edit"
        components={{
          toolbar: (command, disabled, executeCommand) => {
            if (command.keyCommand === 'code') {
              return (
                <button 
                  aria-label="Insert code"
                  disabled={disabled}
                  onClick={(evn) => {
                    evn.stopPropagation();
                    executeCommand(command, command.groupName)
                  }}
                >
                  Code
                </button>
              )
            }
          }
        }}
      />
    </div>
  );
}

Custom Preview Command Tool

import React, { useContext } from "react";
import MDEditor, { commands, EditorContext } from "@uiw/react-md-editor";

const Button = () => {
  const { preview, dispatch } = useContext(EditorContext);
  const click = () => {
    dispatch({
      preview: preview === "edit" ? "preview" : "edit"
    });
  };
  if (preview === "edit") {
    return (
      <svg width="12" height="12" viewBox="0 0 520 520" onClick={click}>
        <polygon
          fill="currentColor"
          points="0 71.293 0 122 319 122 319 397 0 397 0 449.707 372 449.413 372 71.293"
        />
        <polygon
          fill="currentColor"
          points="429 71.293 520 71.293 520 122 481 123 481 396 520 396 520 449.707 429 449.413"
        />
      </svg>
    );
  }
  return (
    <svg width="12" height="12" viewBox="0 0 520 520" onClick={click}>
      <polygon
        fill="currentColor"
        points="0 71.293 0 122 38.023 123 38.023 398 0 397 0 449.707 91.023 450.413 91.023 72.293"
      />
      <polygon
        fill="currentColor"
        points="148.023 72.293 520 71.293 520 122 200.023 124 200.023 397 520 396 520 449.707 148.023 450.413"
      />
    </svg>
  );
};

const codePreview = {
  name: "preview",
  keyCommand: "preview",
  value: "preview",
  icon: <Button />
};

export default function App() {
  const [value, setValue] = React.useState("**Hello world!!!**");
  return (
    <div className="container">
      <div>The system automatically sets the theme</div>
      <MDEditor
        value={value}
        preview="edit"
        extraCommands={[codePreview, commands.fullscreen]}
        onChange={(val) => setValue(val)}
      />
    </div>
  );
}

Editor Font Size

.w-md-editor-text-pre > code,
.w-md-editor-text-input {
  font-size: 23px !important;
  line-height: 24px !important;
}

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.

⚠️ Upgrade v2 to v3 d025430

npm install katex

import React from "react";
import ReactDOM from "react-dom";
import MDEditor from '@uiw/react-md-editor';
import { getCodeString } from 'rehype-rewrite';
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}
\`\`\`
`;

export default function App() {
  return (
    <MDEditor
      value={mdKaTeX}
      previewOptions={{
        components: {
          code: ({ inline, children = [], className, ...props }) => {
            const txt = children[0] || '';
            if (inline) {
              if (typeof txt === 'string' && /^\$\$(.*)\$\$/.test(txt)) {
                const html = katex.renderToString(txt.replace(/^\$\$(.*)\$\$/, '$1'), {
                  throwOnError: false,
                });
                return <code dangerouslySetInnerHTML={{ __html: html }} />;
              }
              return <code>{txt}</code>;
            }
            const code = props.node && props.node.children ? getCodeString(props.node.children) : txt;
            if (
              typeof code === 'string' &&
              typeof className === 'string' &&
              /^language-katex/.test(className.toLocaleLowerCase())
            ) {
              const html = katex.renderToString(code, {
                throwOnError: false,
              });
              return <code style={{ fontSize: '150%' }} dangerouslySetInnerHTML={{ __html: html }} />;
            }
            return <code className={String(className)}>{txt}</code>;
          },
        },
      }}
    />
  );
}

Markdown text to Image

import React, { useState } from "react";
import MDEditor, { commands, ICommand, TextState, TextAreaTextApi } from "@uiw/react-md-editor";
import domToImage from "dom-to-image";

const textToImage: ICommand = {
  name: "Text To Image",
  keyCommand: "text2image",
  buttonProps: { "aria-label": "Insert title3" },
  icon: (
    <svg width="12" height="12" viewBox="0 0 20 20">
      <path fill="currentColor" d="M15 9c1.1 0 2-.9 2-2s-.9-2-2-2-2 .9-2 2 .9 2 2 2zm4-7H1c-.55 0-1 .45-1 1v14c0 .55.45 1 1 1h18c.55 0 1-.45 1-1V3c0-.55-.45-1-1-1zm-1 13l-6-5-2 2-4-5-4 8V4h16v11z" ></path>
    </svg>
  ),
  execute: (state: TextState, api: TextAreaTextApi) => {
    const dom = document.getElementsByClassName("gooooooooo")[0];
    if (dom) {
      domToImage.toJpeg(dom, {}).then((dataUrl) => {
        const link = document.createElement("a");
        link.download = "image.jpg";
        link.href = dataUrl;
        link.click();
      });
    }
  }
};

export default function App() {
  const [value, setValue] = useState('**Hello world!!!**');
  console.log('value::', value)
  return (
    <div className="container">
      <MDEditor
        className="gooooooooo"
        onChange={(newValue = "") => setValue(newValue)}
        value={value}
        commands={[
          textToImage,
          commands.divider
        ]}
      />
    </div>
  );
}

Support Custom Mermaid Preview

Using mermaid to generation of diagram and flowchart from text in a similar manner as markdown

npm install mermaid

import React, { useState, useRef, useEffect } from "react";
import ReactDOM from "react-dom";
import MDEditor from "@uiw/react-md-editor";
import mermaid from "mermaid";

const mdMermaid = `The following are some examples of the diagrams, charts and graphs that can be made using Mermaid and the Markdown-inspired text specific to it. 

\`\`\`mermaid
graph TD
A[Hard] -->|Text| B(Round)
B --> C{Decision}
C -->|One| D[Result 1]
C -->|Two| E[Result 2]
\`\`\`

\`\`\`mermaid
sequenceDiagram
Alice->>John: Hello John, how are you?
loop Healthcheck
    John->>John: Fight against hypochondria
end
Note right of John: Rational thoughts!
John-->>Alice: Great!
John->>Bob: How about you?
Bob-->>John: Jolly good!
\`\`\`
`;

const randomid = () => parseInt(String(Math.random() * 1e15), 10).toString(36);
const Code = ({ inline, children = [], className, ...props }) => {
  const demoid = useRef(`dome${randomid()}`);
  const code = getCode(children);
  const demo = useRef(null);
  useEffect(() => {
    if (demo.current) {
      try {
        const str = mermaid.render(demoid.current, code, () => null, demo.current);
        // @ts-ignore
        demo.current.innerHTML = str;
      } catch (error) {
        // @ts-ignore
        demo.current.innerHTML = error;
      }
    }
  }, [code, demo]);

  if (
    typeof code === "string" && typeof className === "string" &&
    /^language-mermaid/.test(className.toLocaleLowerCase())
  ) {
    return (
      <code ref={demo}>
        <code id={demoid.current} style={{ display: "none" }} />
      </code>
    );
  }
  return <code className={String(className)}>{children}</code>;
};

const getCode = (arr = []) => arr.map((dt) => {
  if (typeof dt === "string") {
    return dt;
  }
  if (dt.props && dt.props.children) {
    return getCode(dt.props.children);
  }
  return false;
}).filter(Boolean).join("");

export default function App() {
  const [value, setValue] = useState(mdMermaid);
  return (
    <MDEditor
      onChange={(newValue = "") => setValue(newValue)}
      textareaProps={{
        placeholder: "Please enter Markdown text"
      }}
      height={500}
      value={value}
      previewOptions={{
        components: {
          code: Code
        }
      }}
    />
  );
}

Support Nextjs

Use examples in nextjs. #52 #224

npm install next-remove-imports
npm install @uiw/[email protected]

// next.config.js
const removeImports = require('next-remove-imports')();
module.exports = removeImports({});

import "@uiw/react-md-editor/markdown-editor.css";
import "@uiw/react-markdown-preview/markdown.css";
import dynamic from "next/dynamic";
import { useState } from "react";

const MDEditor = dynamic(
  () => import("@uiw/react-md-editor"),
  { ssr: false }
);

function HomePage() {
  const [value, setValue] = useState("**Hello world!!!**");
  return (
    <div>
      <MDEditor value={value} onChange={setValue} />
    </div>
  );
}

export default HomePage;

Support dark-mode/night-mode

By default, the dark-mode is automatically switched according to the system. If you need to switch manually, just set the data-color-mode="dark" parameter for body.

<html data-color-mode="dark">

document.documentElement.setAttribute('data-color-mode', 'dark')
document.documentElement.setAttribute('data-color-mode', 'light')

Inherit custom color variables by adding .wmde-markdown-var selector. Setting theme styles with data-color-mode="light".

<div data-color-mode="light">
  <div className="wmde-markdown-var"> </div>
  <MDEditor source="Hello World!" />
</div>

Props

• value: string: The Markdown value.
• onChange?: (value?: string, event?: React.ChangeEvent<HTMLTextAreaElement>, state?: ContextStore): Event handler for the onChange event.
• onHeightChange?: ((value?: CSSProperties['height'], oldValue?: CSSProperties['height'], state?: ContextStore): editor height change listener.
• 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.
• commandsFilter?: (command: ICommand, isExtra: boolean) => false | ICommand: Filter or modify your commands.
• extraCommands?: ICommand[]: Displayed on the right side of the toolbar.
• autoFocus?: true: Can be used to make Markdown Editor focus itself on initialization.
• previewOptions?: ReactMarkdown.ReactMarkdownProps: This is reset @uiw/react-markdown-preview settings.
• textareaProps?: TextareaHTMLAttributes: Set the textarea related props.
• ~~renderTextarea?: (props, opts) => JSX.Element;~~: @deprecated Please use ~~renderTextarea~~ -> components. Use div to replace TextArea or re-render TextArea. #193
• components: re-render textarea/toolbar element. #419
  • textarea Use div to replace TextArea or re-render TextArea
  • toolbar Override the default command element. toolbar < command[].render
  • preview Custom markdown preview. #429
• height?: number=200: The height of the editor. ️⚠️ Dragbar is invalid when height parameter percentage.
• visibleDragbar?: boolean=true: Show drag and drop tool. Set the height of the editor.
• highlightEnable?: boolean=true: Disable editing area code highlighting. The value is false, which increases the editing speed.
• fullscreen?: boolean=false: Show markdown preview.
• overflow?: boolean=true: Disable fullscreen setting body styles
• preview?: 'live' | 'edit' | 'preview': Default value live, Show markdown preview.
• maxHeight?: number=1200: Maximum drag height. The visibleDragbar=true value is valid.
• minHeights?: number=100: Minimum drag height. The visibleDragbar=true value is valid.
• tabSize?: number=2: The number of characters to insert when pressing tab key. Default 2 spaces.
• defaultTabEnable?: boolean=false: If false, the tab key inserts a tab character into the textarea. If true, the tab key executes default behavior e.g. focus shifts to next element.
• hideToolbar?: boolean=false: Option to hide the tool bar.
• enableScroll?: boolean=true: Whether to enable scrolling.

Development

npm run watch     # Listen create type and .tsx files.
npm run css:watch # listen to the component compile and output the .css file
npm run start  # Preview code example.

Related

• @uiw/react-textarea-code-editor: A simple code editor with syntax highlighting.
• @uiw/react-md-editor: A simple markdown editor with preview, implemented with React.js and TypeScript.
• @uiw/react-codemirror: CodeMirror component for React. @codemirror
• @uiw/react-monacoeditor: Monaco Editor component for React.
• @uiw/react-markdown-editor: A markdown editor with preview, implemented with React.js and TypeScript.
• @uiw/react-markdown-preview: React component preview markdown text in web browser.

Contributors

As always, thanks to our amazing contributors!

Made with github-action-contributors.

License

Licensed under the MIT License.