MCP Time Server Node

#!/usr/bin/env node /** * Research script to understand the timezone issue with holiday date comparisons * * Problem: Holiday dates are created without timezone context, causing comparison * failures when business dates are parsed with timezone awareness. */ const { parseISO, format, isSameDay } = require('date-fns'); const { toDate, formatInTimeZone } = require('date-fns-tz'); console.log('=== Holiday Timezone Issue Research ===\n'); // Simulate the problem console.log('1. The Problem:'); const holidayDate = new Date(2025, 0, 1); // Jan 1, 2025 in local time console.log('Holiday created with new Date():', holidayDate.toString()); console.log('Holiday ISO:', holidayDate.toISOString()); const businessDateStr = '2025-01-01'; const businessDateWithTZ = toDate(businessDateStr, { timeZone: 'America/Los_Angeles' }); console.log('\nBusiness date parsed with LA timezone:', businessDateWithTZ.toString()); console.log('Business date ISO:', businessDateWithTZ.toISOString()); console.log('\n2. Comparison using toDateString():'); console.log('Holiday toDateString():', holidayDate.toDateString()); console.log('Business toDateString():', businessDateWithTZ.toDateString()); console.log('Are they equal?', holidayDate.toDateString() === businessDateWithTZ.toDateString()); console.log('\n3. Comparison using isSameDay():'); console.log('isSameDay result:', isSameDay(holidayDate, businessDateWithTZ)); console.log('\n4. The Issue - Different timezone contexts:'); // If the server is in UTC+0 and creates holiday at midnight const holidayUTC = new Date(Date.UTC(2025, 0, 1)); console.log('Holiday in UTC:', holidayUTC.toISOString()); // But business date in LA timezone at start of day const businessLA = toDate('2025-01-01T00:00:00', { timeZone: 'America/Los_Angeles' }); console.log('Business in LA:', businessLA.toISOString()); console.log('These represent different moments in time!'); console.log('\n5. Solution approach - ensure holidays are created in same context:'); // Option 1: Create holidays at noon to avoid timezone boundary issues const holidayNoon = new Date(2025, 0, 1, 12, 0, 0); console.log('Holiday at noon local:', holidayNoon.toString()); // Option 2: Parse holiday strings with same timezone as business dates const holidayWithTZ = toDate('2025-01-01', { timeZone: 'America/Los_Angeles' }); console.log('Holiday parsed with LA timezone:', holidayWithTZ.toString()); console.log('\n6. Test different timezones:'); const timezones = ['UTC', 'America/New_York', 'America/Los_Angeles', 'Asia/Tokyo']; timezones.forEach((tz) => { const date = toDate('2025-01-01', { timeZone: tz }); console.log( `${tz}: ${date.toISOString()} (${formatInTimeZone(date, tz, 'yyyy-MM-dd HH:mm zzz')})`, ); }); console.log('\n7. Testing toDateString() reliability across timezones:'); // Create dates representing "same day" in different ways const date1 = new Date(2025, 0, 1, 0, 0, 0); // Local midnight const date2 = new Date(2025, 0, 1, 23, 59, 59); // Local end of day const date3 = toDate('2025-01-01T12:00:00', { timeZone: 'America/Los_Angeles' }); const date4 = toDate('2025-01-01T12:00:00', { timeZone: 'Asia/Tokyo' }); console.log('Local midnight:', date1.toDateString()); console.log('Local end of day:', date2.toDateString()); console.log('LA noon:', date3.toDateString()); console.log('Tokyo noon:', date4.toDateString()); console.log( 'All show same date string?', date1.toDateString() === date2.toDateString() && date2.toDateString() === date3.toDateString() && date3.toDateString() === date4.toDateString(), ); console.log('\n=== Key Finding ==='); console.log('toDateString() returns the date in the LOCAL timezone of the Date object,'); console.log('regardless of how it was created. This makes it reliable for day comparisons.'); console.log('The issue is that holidays are created without considering the business timezone.'); console.log('\n=== Done ===');