✍️ 🦜 Lexical Loro - Collaborative Plugin for Lexical with Loro CRDT

A collaborative editing plugin for Lexical Rich Editor built with Loro CRDT, providing real-time collaborative editing capabilities with conflict-free synchronization.

Core Components

This package provides three main components for building collaborative text editors:

1. LoroCollaborativePlugin.tsx - A Lexical plugin that integrates Loro CRDT for real-time collaborative editing
2. LexicalModel Python Library - A standalone document model for Lexical content with CRDT capabilities
3. lexical-loro WebSocket Server - A Python server using loro-py for real-time collaboration

Quick Start

Using the Lexical Plugin

import { LoroCollaborativePlugin } from './src/LoroCollaborativePlugin';

function MyEditor() {
  return (
    <LexicalComposer initialConfig={editorConfig}>
      <RichTextPlugin />
      <LoroCollaborativePlugin 
        websocketUrl="ws://localhost:8081"
        docId="my-document"
        username="user1"
      />
    </LexicalComposer>
  );
}

Using the LexicalModel Library

from lexical_loro import LexicalModel

# Create a new document
model = LexicalModel.create_document("my-document")

# Add content
model.add_block({
    "text": "My Document",
    "format": 0,
    "style": ""
}, "heading1")

model.add_block({
    "text": "This is a paragraph.",
    "format": 0,
    "style": ""
}, "paragraph")

# Save to file
model.save_to_file("document.json")

# Load from file
loaded_model = LexicalModel.load_from_file("document.json")

Using the Python Server

# Install the Python package
pip install -e .

# Start the server
lexical-loro-server --port 8081

Examples

For complete working examples, see the src/examples/ directory which contains:

• Full React application with dual editor support
• Server selection interface
• Connection status indicators
• Rich text formatting examples

DISCLAIMER Collaborative Cursors still need fixes, see this issue.

Core Features

• 🔄 Real-time Collaboration: Multiple users can edit the same document simultaneously
• 🚀 Conflict-free: Uses Loro CRDT to automatically resolve conflicts
• 📝 Lexical Integration: Seamless integration with Lexical rich text editor
• 📚 Standalone Library: Use LexicalModel independently for document management
• 🌐 WebSocket Server: Python server for maintaining document state
• 📡 Connection Management: Robust WebSocket connection handling
• ✨ Rich Text Support: Preserves formatting during collaborative editing
• 💾 Serialization: JSON export/import and file persistence
• 🔧 Extensible: Plugin-based architecture for easy customization

Technology Stack

Core Dependencies:

• Lexical: v0.33.1 (Facebook's extensible text editor framework)
• Loro CRDT: v1.5.10 (Conflict-free replicated data types)
• React: 18/19 (for plugin hooks and components)
• Python: 3.8+ with loro-py and websockets

Development Dependencies:

• TypeScript: For type safety
• Vite: For building and development (examples only)
• pytest: Python testing
• ESLint: Code linting

Installation

Core Plugin

The Lexical plugin is a single TypeScript/React component that you can copy into your project:

# Copy the plugin file
cp src/LoroCollaborativePlugin.tsx your-project/src/

Dependencies required:

npm install lexical @lexical/react @lexical/selection loro-crdt react react-dom

Python Server

Install the Python WebSocket server:

# Install from this repository
pip install -e .

# Or install specific dependencies
pip install websockets click loro

Usage

1. Lexical Plugin Integration

Add the plugin to your Lexical editor:

import { LexicalComposer } from '@lexical/react/LexicalComposer';
import { RichTextPlugin } from '@lexical/react/LexicalRichTextPlugin';
import { ContentEditable } from '@lexical/react/LexicalContentEditable';
import { LoroCollaborativePlugin } from './LoroCollaborativePlugin';

const editorConfig = {
  namespace: 'MyEditor',
  theme: {},
  onError: console.error,
};

function CollaborativeEditor() {
  return (
    <LexicalComposer initialConfig={editorConfig}>
      <div className="editor-container">
        <RichTextPlugin
          contentEditable={<ContentEditable className="editor-input" />}
          placeholder={<div className="editor-placeholder">Start typing...</div>}
          ErrorBoundary={() => <div>Error occurred</div>}
        />
        <LoroCollaborativePlugin 
          websocketUrl="ws://localhost:8081"
          docId="shared-document"
          username="user123"
        />
      </div>
    </LexicalComposer>
  );
}

2. Standalone LexicalModel Library

Use the LexicalModel library independently for document management:

from lexical_loro import LexicalModel

# Create a new document
model = LexicalModel.create_document("my-document")

# Add different types of content
model.add_block({
    "text": "My Document",
    "format": 0,
    "style": ""
}, "heading1")

model.add_block({
    "text": "This is a paragraph with **bold** text.",
    "format": 0,
    "style": ""
}, "paragraph")

model.add_block({
    "text": "",
    "format": 0,
    "style": ""
}, "list")

# Serialize to JSON
json_data = model.to_json()

# Save to file
model.save_to_file("document.json")

# Load from file
loaded_model = LexicalModel.load_from_file("document.json")

# Access blocks
for block in loaded_model.get_blocks():
    print(f"{block['type']}: {block.get('text', '')}")

For more examples, see:

• examples/memory_only_example.py - Basic document creation and manipulation
• examples/file_sync_example.py - File persistence and batch operations
• examples/collaboration_example.py - Simulating collaborative editing
• docs/LEXICAL_MODEL_GUIDE.md - Comprehensive documentation

3. Python Server Setup

Start the WebSocket server:

# Default port (8081)
lexical-loro-server

# Custom port
lexical-loro-server --port 8082

# With debug logging
lexical-loro-server --port 8081 --log-level DEBUG

4. Programmatic Server Usage

import asyncio
from lexical_loro import LoroWebSocketServer

async def main():
    server = LoroWebSocketServer(port=8081)
    await server.start()
    print("Server running on ws://localhost:8081")

if __name__ == "__main__":
    asyncio.run(main())

Plugin API

For detailed API documentation, see docs/API.md.

Quick Reference

interface LoroCollaborativePluginProps {
  websocketUrl: string;          // WebSocket server URL
  docId: string;                 // Unique document identifier
  username: string;              // User identifier
  userColor?: string;            // User cursor color (optional)
  debug?: boolean;               // Enable debug logging (optional)
}

Initialization Best Practices

⚠️ Important: Always wait for collaboration initialization before enabling other plugins.

See docs/INITIALIZATION_GUIDE.md for comprehensive guidance on:

• Proper plugin ordering
• Initialization callbacks
• Error handling
• Common anti-patterns to avoid

Examples

For complete working examples and demonstrations, see the src/examples/ directory:

# Run the example application
npm install
npm run example

# This starts both Node.js and Python servers plus a React demo app
# Open http://localhost:5173 to see dual editor interface

The examples include:

• Complete React App: Full collaborative editor with UI
• Server Selection: Switch between Node.js and Python backends
• Dual Editors: Simple text area and rich Lexical editor
• Real-time Demo: Multi-user collaboration testing

See src/examples/README.md for detailed example documentation.

Architecture

EDITOR 1                                           EDITOR 2

loro                                               loro
- node(data: root(1))                              - node(data: root(12))
  - node(data: element(2))                           - node(data: element(22))
    - node(data: text(3))                              - node(data: text(13))
  - node(data: counter(4))                           - node(data: counter(4))

                <---- loro updates via websocket ------>
                <---- loro node ids are the same ------>
             <---- lexical node keys are different ------>

lexical                                            lexical
- root(1)                                          - root(12)
  - element(2)                                       - element(22)
    - text(3)                                          - text(13)
  - counter(4)                                       - counter(49)

Examples

Loro examples

• http://localhost:3000/?isCollab=true

• http://localhost:3000/split/?isCollab=true

Y.js examples (for reference)

• http://localhost:3000/?isCollab=true&useYjs=true

• http://localhost:3000/split/?isCollab=true&useYjs=true