Collaborative POC Study

A proof-of-concept study exploring real-time collaborative document editing systems built with event sourcing architecture. This implementation serves as a research platform for understanding collaborative editing patterns, conflict resolution strategies, and real-time synchronization mechanisms.

Study Focus Areas

📝 Block-Based Document System

• Block Creation: Users can create text blocks that form the document structure
• Content Editing: Real-time editing of individual blocks with change tracking
• Block Management: Insert, update, delete, and reorder blocks within documents
• Position-Aware Operations: Blocks can be inserted at specific positions

🔒 Conflict Resolution System

• Block Locking: Exclusive editing locks prevent concurrent modifications
• First-Lock-Wins: Clear conflict resolution strategy for competing edits
• Lock Expiration: Automatic 30-second timeouts prevent stuck locks
• Lock Management: Clean acquisition and release workflows

✏️ Real-Time Draft System

• Live Drafts: Track users' typing in real-time before committing changes
• Draft Synchronization: All users see live drafts from other collaborators
• Draft Commits: Convert drafts to permanent block content
• Multi-User Drafts: Handle multiple users drafting on different blocks

👥 Multi-User Collaboration

• User Management: Add/remove users with unique IDs and visual colors
• User Presence: Track active/inactive user states
• Concurrent Operations: Support multiple users working simultaneously
• User Attribution: Track which user made each change

⚡ Event Sourcing Architecture

• Immutable Event Log: All changes stored as events, never mutated
• State Projection: Current document state derived from event replay
• Version Control: Sequential event versioning for consistency
• State Reconstruction: Complete state can be rebuilt from events

Test Coverage

The system includes comprehensive tests covering all major functionality:

🏗️ Core System Tests (core-system.test.ts)

• Event Sourcing Foundation: Event dispatch, atomic updates, versioning
• Block Management: CRUD operations, content updates, ordering
• Locking System: Lock acquisition, conflicts, expiration handling
• Draft System: Real-time updates, commits, cleanup
• Performance: Bulk operations (50+ blocks under 100ms)
• Data Integrity: Event replay and state reconstruction

👥 Multi-User Collaboration Tests (multi-user-collaboration.test.ts)

• User Management: Adding/removing users, unique IDs, color assignment
• Concurrent Operations: Multiple users creating/editing blocks simultaneously
• Collaborative Locking: Lock conflicts and resolution across users
• Real-Time Draft Sharing: Live draft visibility between users
• Complex Workflows: Complete collaborative editing sessions
• Stress Testing: High-load scenarios with many users and operations

🚀 Real-Time Sync Tests (real-time-sync-*.test.ts)

• Async Operations: Simulated network delays with proper timing
• Cross-Tab Synchronization: Multi-tab consistency verification
• Race Conditions: Lock competition with realistic timing
• Event Ordering: Proper sequencing of concurrent operations
• State Consistency: Verification across all connected clients

Technical Architecture

Core Implementation

app/
├── stores/
│   ├── event-core.store.ts      # Event sourcing engine
│   ├── document.store.ts        # Block and document operations
│   ├── collaboration.store.ts   # User, lock, and draft management
│   └── index.ts                # Store exports
├── collaboration.types.ts       # Core data structures
└── event.types.ts              # Event definitions and utilities

Test Infrastructure

test/
├── test-helpers.ts         # Shared testing utilities
├── setup.ts               # Test configuration
└── *.test.ts              # Comprehensive test suites

Legacy Components (Moved to app/legacy/)

The UI components have been moved to app/legacy/ as this project focuses on the core collaborative editing logic and architecture rather than user interface implementation.

Key Implementation Details

Event Sourcing Pattern

• All changes captured as immutable events with metadata
• Current state computed by reducing over the event log
• Full audit trail and replay capabilities
• Version control through sequential event numbering

Lock-Based Conflict Resolution

• Optimistic locking allows users to attempt any operation
• Block-level exclusive locks prevent concurrent modifications
• First-to-lock wins in conflict scenarios
• Automatic cleanup prevents orphaned locks

Real-Time Draft System

• Drafts tracked separately from committed content
• Live updates shared across all users instantly
• Clean commit workflow updates block content atomically
• Draft cleanup prevents memory leaks

Getting Started

# Install dependencies
pnpm install

# Run all tests
pnpm run test

# Run tests with detailed output
pnpm run test:run

# Type checking
pnpm run typecheck

# Code quality checks
pnpm run check

Purpose

This project serves as a Proof of Concept (POC) and Study for:

• Research: Exploring collaborative editing architectures and patterns
• Learning: Understanding event sourcing in real-time systems
• Prototyping: Testing different conflict resolution strategies
• Documentation: Creating reference implementations for collaborative features

Test Results

All tests pass with comprehensive coverage:

• ✅ Event sourcing and state management
• ✅ Block operations and document management
• ✅ Multi-user collaboration workflows
• ✅ Real-time synchronization and conflict resolution
• ✅ Performance under load
• ✅ Data consistency and integrity

The test suite validates that the system properly handles complex collaborative scenarios and maintains consistency across all operations.