JarCasting 
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 ontextareaencapsulation, does not depend on any modern code editors. -
🚧 Does not depend on theuiwcomponent 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(/^\$\$(.*)\$\$/, '$1'), {
throwOnError: false,
});
return <code dangerouslySetInnerHTML={{ __html: html }} />;
}
return children;
},
code: ({ language, value, children }) => {
if (language && language.toLocaleLowerCase() === 'katex') {
const html = katex.renderToString(value, {
throwOnError: false,
});
return (
<pre>
<code dangerouslySetInnerHTML={{ __html: html }} />
</pre>
);
}
const props = {
className: language ? `language-${language}` : '',
};
return (
<pre {...props}>
<code {...props}>{value}</code>
</pre>
);
},
}
export default function App() {
return (
<MDEditor
value={mdKaTeX}
previewOptions={{ renderers }}
/>
);
}
Markdown text to Imgage
import React from "react";
import MDEditor, { commands, ICommand, TextState, TextApi } 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: TextApi) => {
const dom = document.getElementsByClassName("w-md-editor")[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() {
return (
<div className="container">
<MDEditor
value="**Hello world!!!**"
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
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 theonChangeevent.commands?: ICommand[]: An array ofICommand, which, each one, contain acommandsproperty. If no commands are specified, the default will be used. Commands are explained in more details below.autoFocus?: true: Can be used to makeMarkdown Editorfocus itself on initialization.previewOptions?: ReactMarkdown.ReactMarkdownProps: This is reset @uiw/react-markdown-preview settings.textareaProps?: TextareaHTMLAttributes: Set thetextarearelated props.height?: number=200: The height of the editor.visiableDragbar?: boolean=true: Show drag and drop tool. Set the height of the editor.highlightEnable?: boolean=true: Disable editing area code highlighting. The value isfalse, which increases the editing speed.fullscreen?: boolean=false: Show markdown preview.preview?: 'live' | 'edit' | 'preview': Default valuelive, Show markdown preview.maxHeight?: number=1200: Maximum drag height. ThevisiableDragbar=truevalue is valid.minHeights?: number=100: Minimum drag height. ThevisiableDragbar=truevalue is valid.tabSize?: number=2: The number of characters to insert when pressing tab key. Default2spaces.hideToolbar?: boolean=false: Option to hide the tool bar.
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-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.
License
Licensed under the MIT License.
