ÿþ# LESSONS.md
Date: 2025-09-19
Issue: Time Tracking infinite loading

## What Went Wrong
- JavaScript fetch() doesn't include cookies by default
- API requires authentication but fetch wasn't sending session
- Result: 302 redirect to login, spinner never resolved

## What We Learned
1. Always include credentials: 'same-origin' for authenticated APIs
2. Check network tab in browser for 302 redirects
3. Test API endpoints directly to see actual response

## Time Spent
- Investigation: 15 minutes
- Root cause found quickly by testing endpoint
- Fix: 2 minutes

## Prevention
- Create a standard fetch wrapper with auth included
- Add this to developer checklist for new API calls
- Consider using axios which handles this better