The Samoa Date Line Jump

// This breaks on Samoa's date jump
function generateDailyReports(startDate, endDate) {
  const reports = [];
  let currentDate = new Date(startDate);
  
  while (currentDate <= endDate) {
    reports.push(generateReport(currentDate));
    
    // This assumes every day exists!
    currentDate.setDate(currentDate.getDate() + 1);
  }
  
  return reports;
}

// December 30, 2011 never existed in Samoa
// This loop would generate a report for a non-existent day

// Safe approach using proper timezone libraries
import { DateTime } from 'luxon';

function generateDailyReports(startDate, endDate, timezone) {
  const reports = [];
  let current = DateTime.fromISO(startDate, { zone: timezone });
  const end = DateTime.fromISO(endDate, { zone: timezone });
  
  while (current <= end) {
    // Only generate reports for days that actually exist
    if (current.isValid) {
      reports.push(generateReport(current));
    }
    
    // Add 1 day in the local timezone
    current = current.plus({ days: 1 });
  }
  
  return reports;
}

// This properly handles Samoa's missing December 30th

from datetime import datetime, timedelta
import pytz

def safe_date_range(start_date, end_date, timezone_name):
    """Generate dates that actually exist in the given timezone"""
    tz = pytz.timezone(timezone_name)
    current = tz.localize(start_date)
    end = tz.localize(end_date)
    
    while current <= end:
        try:
            # Verify the date actually exists
            tz.localize(current.replace(tzinfo=None))
            yield current
        except pytz.AmbiguousTimeError:
            # Handle DST ambiguity
            yield tz.localize(current.replace(tzinfo=None), is_dst=False)
        except pytz.NonExistentTimeError:
            # Skip non-existent dates (like Samoa's Dec 30, 2011)
            pass
        
        current += timedelta(days=1)