CKEditor 5 mathematical feature ·

ckeditor5-math is a TeX-based mathematical plugin for CKEditor 5. You can use it to insert, edit, and view mathematical equations and formulas. This plugin supports MathJax, KaTeX and custom typesetting engines.

Table of contents

• Features
• Demos
• Screenshots
• Requirements
• Examples
• Installation
  • Styles for Lark theme
• Configuration & Usage
  • Plugin options
  • Available typesetting engines
  • Supported input and output formats
• Paste support
  • From plain text
• Autoformat support
• Preview workaround

Features

• TeX syntax
• Inline and display equations
• Preview view
• Multiple typesetting engines
• Have multiple input and output format
• Paste support
  • from plain text
• Autoformat support

Demos

• Classic editor with MathJax
• Classic editor with KaTex
• Balloon block editor with KaTex

Screenshots

Requirements

• Use same major version as your CKEditor 5 build

If you get duplicated modules error, you have mismatching versions.

Examples

Link to examples repository

Installation

Use official classic or inline build as a base:

• CKEditor 5 classic editor build
• CKEditor 5 inline editor build

Install plugin with NPM or Yarn

npm install @isaul32/ckeditor5-math --save-dev

yarn add @isaul32/ckeditor5-math --dev

Add import into ckeditor.js file

import Math from '@isaul32/ckeditor5-math/src/math';
import AutoformatMath from '@isaul32/ckeditor5-math/src/autoformatmath';

Add it to built-in plugins

InlineEditor.builtinPlugins = [
	// ...
	Math,
	AutoformatMath
];

Add math button to toolbar

InlineEditor.defaultConfig = {
	toolbar: {
		items: [
			// ...
			'math'
		]
	}
};

Styles for Lark theme

Copy theme/ckeditor5-math folder from https://github.com/isaul32/ckeditor5/tree/master/packages/ckeditor5-theme-lark to your lark theme repository

Using DLL builds

Use the official DLL build and additionally load the math plugin:

<script src="path/to/node_modules/@isaul32/ckeditor5-math/build/math.js"></script>
<script>
CKEditor5.editorClassic.ClassicEditor
	.create(editorElement, {
		plugins: [
			CKEditor5.math.Math,
			...
		],
		...
	});
</script>

Configuration & Usage

Plugin options

InlineEditor.defaultConfig = {
	// ...
	math: {
		engine: 'mathjax', // or katex or function. E.g. (equation, element, display) => { ... }
		lazyLoad: undefined, // async () => { ... }, called once before rendering first equation if engine doesn't exist. After resolving promise, plugin renders equations.
		outputType: 'script', // or span
		className: 'math-tex', // class name to use with span output type, change e.g. MathJax processClass (v2) / processHtmlClass (v3) is set
		forceOutputType: false, // forces output to use outputType
		enablePreview: true, // Enable preview view
		previewClassName: [], // Class names to add to previews
		popupClassName: [], // Class names to add to math popup balloon
		katexRenderOptions: {}  // KaTeX only options for katex.render(ToString)
	}
}

Available typesetting engines

MathJax

• Tested with latest 2.7
• Has experimental (CHTML, SVG) support for 3.0.0 or newer version

KaTeX

• Tested with version 0.12.0

• katexRenderOptions - pass options.

  InlineEditor.defaultConfig = {
  	// ...
  	math: {
  		engine: 'katex'
  		katexRenderOptions: {
  			macros: {
  				"\\neq": "\\mathrel{\\char`≠}",
  			},
  		},
  	}
  }

Custom typesetting

Custom typesetting is possible to implement with engine config. For example, custom typesetting feature can be used when use back end rendering.

InlineEditor.defaultConfig = {
	// ...
	math: {
		engine: ( equation, element, display, preview ) => {
			// ...
		}
	}
}

• equation is equation in TeX format without delimiters.
• element is DOM element reserved for rendering.
• display is boolean. Typesetting should be inline when false.
• preview is boolean. Rendering in preview when true.

Supported input and output formats

Supported input and output formats are:

<!-- MathJax style http://docs.mathjax.org/en/v2.7-latest/advanced/model.html#how-mathematics-is-stored-in-the-page -->
<script type="math/tex">\sqrt{\frac{a}{b}}</script>
<script type="math/tex; mode=display">\sqrt{\frac{a}{b}}</script>

<!-- CKEditor 4 style https://ckeditor.com/docs/ckeditor4/latest/features/mathjax.html -->
<span class="math-tex">\( \sqrt{\frac{a}{b}} \)</span>
<span class="math-tex">\[ \sqrt{\frac{a}{b}} \]</span>

Paste support

From plain text

Paste TeX equations with delimiters. For example:

\[ x=\frac{-b\pm\sqrt{b^2-4ac}}{2a} \]

or

\( x=\frac{-b\pm\sqrt{b^2-4ac}}{2a} \)

Autoformat support

Inline mode

Ctrl+M can be used to add easily math formulas in inline mode.

Display mode

Autoformat for math can be used to add formula in display mode on a new line by adding \[ or $$. This feature requires additional autoformat plugin to be added.

Add following lines into your build

// ...
import AutoformatMath from '@isaul32/ckeditor5-math/src/autoformatmath';

InlineEditor.builtinPlugins = [
	// ...
	AutoformatMath
];

or use it with DLL build

<script src="path/to/node_modules/@isaul32/ckeditor5-math/build/math.js"></script>
<script>
CKEditor5.editorInline.InlineEditorEditor
	.create(editorElement, {
		plugins: [
			CKEditor5.math.AutoformatMath,
			...
		],
		...
	});
</script>

Preview workaround

.ck-reset_all * css rules from ckeditor5-ui and ckeditor5-theme-lark break rendering in preview mode.

My solution for this is use rendering element outside of CKEditor DOM and place it to right place by using absolute position. Alternative solution could be using iframe, but then typesetting engine's scripts and styles have to copy to child document.

TypeScript users

ckeditor5-math does not have typings yet. TypeScript builds of CKEditor will see this:

src/ckeditor.ts:63:18 - error TS7016: Could not find a declaration file for module '@isaul32/ckeditor5-math/src/math'.
'/path/to/your/project/node_modules/@isaul32/ckeditor5-math/src/math.js' implicitly has an 'any' type.

Try `npm i --save-dev @types/isaul32__ckeditor5-math` if it exists or add a new declaration (.d.ts) file containing
`declare module '@isaul32/ckeditor5-math/src/math';`

Workaround for typings

1. Create a d.ts declaration file, e.g. typings/ckeditor5-math.d.ts

   declare module '@isaul32/ckeditor5-math';
   declare module '@isaul32/ckeditor5-math/src/math';
   declare module '@isaul32/ckeditor5-math/src/autoformatmath';

2. In your tsconfig.json's root-level include option, make sure your declaration file is covered, e.g.

   {
     "extends": "ckeditor5/tsconfig.json",
     "include": [
       "src",
       "typings",
       "../../typings"
      ]
   }

Development

Contributions, improvements and bug fixes are welcome. To aid in this, try out our developer environment w/ live reload support and CKEditor 5 inspector.

To enter a development loop with hot reload support:

• git clone https://github.com/isaul32/ckeditor5-math.git
• cd ckeditor5-math
• yarn
• yarn start
• http://localhost:8080