Progressive Web Application with CRDT Sync

A PWA with offline-first support and CRDT-based sync over a shared WebSocket connection.

Installation

Prerequisite: Node.js 18+

1. Clone this repository
2. Install dependencies: npm i
3. Start the development server: node server.js
4. Open http://localhost:8000 in your browser

Features

• Installable app: a native App-like UX
• Real-time notifications using Websockets
• Offline support (works without an internet or server)
• Background sync and caching with service worker and CRDT
• Broad device/browser support, Linux, MacOS, Win, iOS, Android
• Single WebSocket connection shared across tabs
• Automatic reconnection, retrieving lost messages
• HTTPS headers and CORS support
• Reactions: like, dislike, etc. with counters

TODO

• Changes to ./Application/static/domain.js
  • Move Logger to logger.js and export it as a singleton
  • Decompose ChatApplication: extract ui.js and domain.js
  • Domain logic should live in domain.js
  • Visualization and UI logic should live in ui.js
• Unify CRDT implementations and reuse across the app, service worker, and server
  • Extract lww and counter into crdt.js; apply the Strategy pattern
  • Import crdt.js from the service worker and server to reuse code
• Changes to pwa.js
  • Extract utility helpers (e.g., ID generation) into utils.js
  • Move EventEmitter into events.js

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