MCP Time Server Node

const { formatRelative, parseISO } = require('date-fns'); const { toDate, toZonedTime, formatInTimeZone } = require('date-fns-tz'); console.log('Testing formatRelative with timezones\n'); // Test date: Monday, January 1, 2024 at 9:30 AM UTC const testDateStr = '2024-01-01T09:30:00.000Z'; const testDate = parseISO(testDateStr); // Base date for relative formatting (now): January 3, 2024 at 2:00 PM UTC const nowStr = '2024-01-03T14:00:00.000Z'; const now = parseISO(nowStr); console.log('Test Date (UTC):', testDate.toISOString()); console.log('Now (UTC):', now.toISOString()); console.log(''); // Test 1: Basic formatRelative without timezone consideration console.log('=== Test 1: Basic formatRelative (no timezone) ==='); const basic = formatRelative(testDate, now); console.log('Result:', basic); console.log(''); // Test 2: Using toDate for timezone conversion (current approach) console.log('=== Test 2: Using toDate (current approach) ==='); function testToDateApproach(timezone) { console.log(`\nTimezone: ${timezone}`); const zonedDate = toDate(testDate, { timeZone: timezone }); const zonedNow = toDate(now, { timeZone: timezone }); console.log('zonedDate:', zonedDate.toISOString()); console.log('zonedNow:', zonedNow.toISOString()); // Calculate time difference const timeDiff = zonedDate.getTime() - zonedNow.getTime(); console.log('Time difference (ms):', timeDiff); // Create adjusted date const adjustedDate = new Date(Date.now() + timeDiff); console.log('adjustedDate:', adjustedDate.toISOString()); const result = formatRelative(adjustedDate, new Date()); console.log('Result:', result); } testToDateApproach('America/New_York'); testToDateApproach('Asia/Tokyo'); testToDateApproach('UTC'); console.log(''); // Test 3: Using toZonedTime console.log('=== Test 3: Using toZonedTime ==='); function testToZonedTimeApproach(timezone) { console.log(`\nTimezone: ${timezone}`); const zonedDate = toZonedTime(testDate, timezone); const zonedNow = toZonedTime(now, timezone); console.log('zonedDate:', zonedDate.toISOString()); console.log('zonedNow:', zonedNow.toISOString()); const result = formatRelative(zonedDate, zonedNow); console.log('Result:', result); } testToZonedTimeApproach('America/New_York'); testToZonedTimeApproach('Asia/Tokyo'); testToZonedTimeApproach('UTC'); console.log(''); // Test 4: Understanding the real issue console.log('=== Test 4: Understanding the issue ==='); console.log('\nThe problem is that formatRelative uses the LOCAL timezone of the system'); console.log('for formatting, regardless of the dates passed to it.\n'); // Test 5: Custom baseDate with options console.log('=== Test 5: Using baseDate option ==='); function testWithBaseDate(timezone) { console.log(`\nTimezone: ${timezone}`); // formatRelative with baseDate option const result = formatRelative(testDate, now); console.log('Result:', result); // Show what the dates look like in the target timezone const dateInTz = formatInTimeZone(testDate, timezone, 'PPPPpppp'); const nowInTz = formatInTimeZone(now, timezone, 'PPPPpppp'); console.log('Date in timezone:', dateInTz); console.log('Now in timezone:', nowInTz); } testWithBaseDate('America/New_York'); testWithBaseDate('Asia/Tokyo'); console.log(''); // Test 6: The correct approach - format in timezone first, then describe console.log('=== Test 6: Correct approach - format strings in timezone ==='); function correctApproach(timezone) { console.log(`\nTimezone: ${timezone}`); // Get the formatted strings in the target timezone const dateStr = formatInTimeZone(testDate, timezone, "EEEE 'at' h:mm a"); const dayOfWeek = formatInTimeZone(testDate, timezone, 'EEEE'); const time = formatInTimeZone(testDate, timezone, 'h:mm a'); console.log('Formatted date string:', dateStr); console.log('Day of week:', dayOfWeek); console.log('Time:', time); // Calculate days difference const msPerDay = 24 * 60 * 60 * 1000; const daysDiff = Math.floor((now - testDate) / msPerDay); console.log('Days difference:', daysDiff); // Build relative string based on days difference let relative; if (daysDiff === 0) { relative = `today at ${time}`; } else if (daysDiff === 1) { relative = `yesterday at ${time}`; } else if (daysDiff === -1) { relative = `tomorrow at ${time}`; } else if (daysDiff < 7 && daysDiff > 0) { relative = `last ${dayOfWeek} at ${time}`; } else if (daysDiff > -7 && daysDiff < 0) { relative = `${dayOfWeek} at ${time}`; } else { relative = formatInTimeZone(testDate, timezone, 'MM/dd/yyyy'); } console.log('Relative result:', relative); } correctApproach('America/New_York'); correctApproach('Asia/Tokyo'); correctApproach('UTC'); console.log(''); // Test 7: Edge cases with different base dates console.log('=== Test 7: Edge cases ==='); const testCases = [ { date: '2024-01-03T09:00:00Z', base: '2024-01-03T14:00:00Z', desc: 'Same day' }, { date: '2024-01-02T09:00:00Z', base: '2024-01-03T14:00:00Z', desc: 'Yesterday' }, { date: '2024-01-04T09:00:00Z', base: '2024-01-03T14:00:00Z', desc: 'Tomorrow' }, { date: '2023-12-28T09:00:00Z', base: '2024-01-03T14:00:00Z', desc: 'Last week' }, ]; testCases.forEach(({ date, base, desc }) => { console.log(`\n${desc}:`); const d = parseISO(date); const b = parseISO(base); console.log('Native formatRelative:', formatRelative(d, b)); // Show in different timezones console.log('NY time:', formatInTimeZone(d, 'America/New_York', "EEEE 'at' h:mm a")); console.log('Tokyo time:', formatInTimeZone(d, 'Asia/Tokyo', "EEEE 'at' h:mm a")); });