A simple react.js markdown editor with preview

by React

react-md-editor

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.

View Demo View Github

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

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>
  );
}

Custom Toolbars

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

const title3: 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: TextState, api: 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={[
          // Custom Toolbars
          title3,
          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: commands.TextState, api: commands.TextApi)  => {
              console.log('>>>>>>update>>>>>', state)
            },
            buttonProps: { 'aria-label': 'Insert title'}
          }),
        ]}
      />
    </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 }}
    />
  );
}

Support Custom Mermaid Preview

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

import React 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 renderers = {
  code: ({ children, language, value }) => {
    if (language.toLocaleLowerCase() === "mermaid") {
      const Elm = document.createElement("div");
      Elm.id = "demo";
      const svg = mermaid.render("demo", value);
      return (
        <pre>
          <code dangerouslySetInnerHTML={{ __html: svg }} />
        </pre>
      );
    }
    return children;
  }
};

export default function App() {
  return (
    <MDEditor
      height={500}
      value={mdMermaid || ""}
      previewOptions={{ renderers: renderers }}
    />
  );
}

ReactDOM.render(<App />, document.getElementById("container"));

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 @uiw/react-markdown-preview 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.
  • hideToolbar?: boolean=false: Option to hide the tool bar.

Development

npm run watch  # Listen create type and .tsx files.
npm run start  # Preview code example.

GitHub