cm123go

Transport app for Chelmsford UK

Getting Started

npm install
npm run dev

Scripts

Command	Description
npm run dev	Start development server
npm run build	Production build
npm run preview	Preview production build
npm test	Run tests in watch mode
npm run test:run	Run tests once
npm run test:coverage	Generate coverage report
npm run lint	Check for lint errors
npm run lint:fix	Fix lint errors
npm run format	Format code with Prettier
npm run typecheck	TypeScript type checking
npm run knip	Find unused code
npm run check	Run all checks

Project Structure

src/
├── main.ts          # Application entry point
├── main.test.ts     # Example test
├── api/             # External API clients
├── core/            # Core business logic
├── config/          # Configuration loading with Zod
├── utils/           # Logger and helper utilities
└── types/           # Shared type definitions

Architecture

How It Works

1. App loads config and gets user location via browser Geolocation API
2. Reverse geocodes location to display UK postcode (via postcodes.io)
3. Finds nearest bus stops in both directions (up to 4 stops)
4. Fetches real-time departures with fallback chain:
   • First Bus API - real-time for First Essex buses (primary)
   • BODS SIRI-VM + GTFS - vehicle positions + timetables (fallback)
   • GTFS scheduled times - static timetables (last resort)

External APIs

API	Purpose
First Bus	Real-time departure times
BODS SIRI-VM	Real-time vehicle positions
BODS GTFS	Static timetable data
NAPTAN	Bus stop data (pre-bundled)
postcodes.io	Geocoding (free, no API key)

Caching

Uses IndexedDB for offline-first experience:

• Bus stops: 7 days
• Departures: 60 seconds
• Timetables: 1 day

PWA Support

This app is configured as a Progressive Web App. To complete PWA setup:

1. Add icon files to public/icons/:
   • icon-192.png (192x192)
   • icon-512.png (512x512)

License

MIT