Pacer

Triathlon pacing calculator as a Progressive Web App. Calculates total race time from swim, bike, and run inputs with transition times.

Features

• 4 distances: Sprint, Olympic, Half Ironman, Ironman
• Flexible input: Switch between pace (min/100m, km/h, min/km) and duration per discipline
• Transition times: T1 (Swim > Bike) and T2 (Bike > Run) with defaults
• Persistent state: All inputs are saved to localStorage and restored on next visit
• Installable: Add to iPhone/Android home screen for app-like experience
• Offline capable: Works without internet after first load

Tech Stack

• Single-file HTML/CSS/JS — no build tools, no dependencies, no frameworks
• Service Worker for offline caching
• Web App Manifest for home screen installation
• Google Fonts (Inter, JetBrains Mono)

Local Development

python3 -m http.server 8000

Open http://localhost:8000 in your browser.

Note: Service Workers require HTTP (not file://), so a local server is necessary.

Deploy to GitHub Pages

git init
git add index.html manifest.json sw.js icon-192.png icon-512.png README.md
git commit -m "Initial commit"
gh repo create pacer --public --source=. --push
gh api repos/{owner}/pacer/pages -X POST -f "source[branch]=main" -f "source[path]=/"

The app will be available at https://<username>.github.io/pacer/.

Install on iPhone

1. Open the URL in Safari
2. Tap "Share" > "Add to Home Screen"
3. The app runs fullscreen and works offline

Project Structure

index.html      Main app (HTML + CSS + JS)
manifest.json   PWA manifest
sw.js           Service worker for offline support
icon-192.png    App icon 192x192
icon-512.png    App icon 512x512