How to Render LaTeX/KaTeX Math Equations in Tiptap: A Complete Guide

The Katex extension in reactjs-tiptap-editor provides a complete client-side solution for rendering LaTeX/KaTeX mathematics inside Tiptap using a custom node view, toolbar dialog, and real-time preview capabilities.

The reactjs-tiptap-editor package ships with a dedicated Katex extension that enables first-class LaTeX math support without external dependencies beyond the official KaTeX library. This extension implements a full-stack rendering pipeline that handles everything from input parsing to HTML generation, allowing users to write mathematical expressions using standard LaTeX syntax directly within the editor.

Architecture of the Katex Extension

The implementation follows a three-layer architecture that separates data modeling, rendering logic, and user interface concerns.

Extension Definition Layer

The core extension logic resides in [src/extensions/Katex/Katex.ts](https://github.com/hunghg255/reactjs-tiptap-editor/blob/main/src/extensions/Katex/Katex.ts). This file declares an inline node named katex that stores two HTML attributes: text (the LaTeX expression) and macros (optional macro definitions). It registers a setKatex command, an input rule triggered by $katex$, and a React node view factory.

React Node View Layer

[src/extensions/Katex/components/KatexWrapper.tsx](https://github.com/hunghg255/reactjs-tiptap-editor/blob/main/src/extensions/Katex/components/KatexWrapper.tsx) implements the KatexNodeView component. This component retrieves the stored LaTeX string from node attributes, processes it through katex.renderToString, and injects the generated HTML using dangerouslySetInnerHTML. The resulting span.katex element is draggable, selectable, and editable.

Toolbar UI Layer

The user interface is provided by [src/extensions/Katex/components/RichTextKatex.tsx](https://github.com/hunghg255/reactjs-tiptap-editor/blob/main/src/extensions/Katex/components/RichTextKatex.tsx). This component renders a toolbar button that opens a modal dialog where users can input LaTeX expressions and define macros. The dialog features a real-time preview using the same KaTeX engine (v0.16.27) as the node view.

Data Flow

When a user inserts a formula:

1. The toolbar dialog captures the LaTeX expression and optional macros
2. The dialog executes editor.chain().focus().setKatex({ text, macros }).run()
3. The setKatex command inserts a katex node with encoded attributes
4. The React node view decodes attributes and calls katex.renderToString
5. The rendered HTML appears as an inline, draggable element in the editor

Implementation Guide

Follow these steps to enable LaTeX/KaTeX math equations in your Tiptap editor.

Install Dependencies

While reactjs-tiptap-editor includes katex (v0.16.27) as a dependency, you must manually import the CSS and ensure peer dependencies are available:

npm install katex @tiptap/react @tiptap/core

Import the Extension and Styles

Import the Katex extension, toolbar component, and required CSS:

import { Katex, RichTextKatex } from 'reactjs-tiptap-editor/katex';
import 'katex/dist/katex.min.css';

Configure Editor Extensions

Add Katex to your Tiptap extensions array:

import { useEditor } from '@tiptap/react';
import { Document, Text, Paragraph } from '@tiptap/extensions';
import { Katex } from 'reactjs-tiptap-editor/katex';

const editor = useEditor({
  extensions: [
    Document,
    Text,
    Paragraph,
    // other extensions...
    Katex,
  ],
  content: '',
});

Add the Toolbar Button

Render the RichTextKatex component within your toolbar to provide the LaTeX input dialog:

const RichTextToolbar = () => (
  <>
    {/* other toolbar buttons */}
    <RichTextKatex />
  </>
);

Usage Examples

Users can enter various LaTeX expressions through the dialog:

• Simple equation: E = mc^2 renders as E = mc²
• Integral: \int_{0}^{\infty} e^{-x} dx = 1 renders the corresponding integral notation
• Custom macros: \newcommand{\R}{\mathbb{R}} \R renders the real number symbol ℝ

The dialog's previewContent updates in real-time using the same rendering logic as the node view, ensuring WYSIWYG accuracy before insertion.

Key Implementation Files

Understanding these source files helps with customization and debugging:

• src/extensions/Katex/Katex.ts: Defines the katex node schema, setKatex command, and input rules
• src/extensions/Katex/components/KatexWrapper.tsx: React node view that executes katex.renderToString and manages DOM insertion
• src/extensions/Katex/components/RichTextKatex.tsx: Toolbar button and modal dialog with real-time preview
• docs/extensions/Katex/index.md: Official documentation with import syntax and configuration examples

Summary

• Import path: Use reactjs-tiptap-editor/katex for both the extension and toolbar components
• Required CSS: Always import katex/dist/katex.min.css for proper equation styling
• Command API: Insert equations via editor.chain().focus().setKatex({ text, macros }).run()
• Real-time preview: The toolbar dialog provides live KaTeX rendering before insertion
• Node attributes: The extension stores LaTeX source in text and macro definitions in macros attributes
• File locations: Core logic is in src/extensions/Katex/Katex.ts with UI components in the components/ subdirectory

Frequently Asked Questions

How do I edit an existing KaTeX equation in the editor?

Double-click or select the rendered equation node and click the Katex toolbar button. The dialog will reopen with the current text and macros values pre-populated, allowing you to modify the LaTeX source and update the rendering via the setKatex command.

Does this extension support both inline and block equations?

Yes. The katex node is defined as an inline node in src/extensions/Katex/Katex.ts, but it can be configured for block contexts by modifying the node specification or using Tiptap's node wrapping commands. The underlying katex.renderToString method handles both display and inline math modes based on the LaTeX syntax provided.

Why is my equation not rendering after installation?

Ensure you have imported the KaTeX CSS file (import 'katex/dist/katex.min.css'). Without this stylesheet, the HTML generated by katex.renderToString in KatexWrapper.tsx will lack the necessary fonts and positioning rules. Also verify that the Katex extension is included in your Tiptap extensions array.

Can I define custom LaTeX macros?

Yes. The setKatex command accepts a macros object parameter that gets stored in the node's HTML attributes. These macros are passed to katex.renderToString in KatexWrapper.tsx, allowing you to define reusable commands like \newcommand{\R}{\mathbb{R}} that persist with the specific equation node.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}