MCP Time Server Node

# formatRelative with Timezones (Verified 2025-07-19) **Critical Discovery**: `formatRelative()` cannot be used for timezone-aware relative formatting. **Key Findings**: 1. **formatRelative Always Uses System Timezone**: - Regardless of the Date objects passed to it - No way to specify target timezone - Always formats times in the system's local timezone 2. **toDate() Behavior**: - `toDate(date, { timeZone: 'X' })` does NOT convert the date - Returns the same Date object (verified with ===) - The timezone option is misleading/useless for this use case 3. **The Broken Approach**: ```typescript // This DOES NOT WORK const zonedDate = toDate(date, { timeZone: timezone }); const zonedNow = toDate(now, { timeZone: timezone }); const timeDiff = zonedDate.getTime() - zonedNow.getTime(); const adjustedDate = new Date(Date.now() + timeDiff); formatRelative(adjustedDate, new Date()); // Always returns dates formatted in system timezone ``` 4. **Correct Implementation Requires Manual Building**: ```typescript // Format time in target timezone const timeStr = formatInTimeZone(date, timezone, 'h:mm a'); const dayOfWeek = formatInTimeZone(date, timezone, 'EEEE'); // Calculate days difference const msPerDay = 24 * 60 * 60 * 1000; const daysDiff = Math.round((baseDate - date) / msPerDay); // Build relative string manually if (daysDiff === 0) return `today at ${timeStr}`; if (daysDiff === 1) return `yesterday at ${timeStr}`; if (daysDiff === -1) return `tomorrow at ${timeStr}`; // etc. ``` 5. **Day Difference Calculation**: - Must use UTC dates for accurate day counting - Consider using start of day for both dates - Round the result to handle DST transitions 6. **Implementation Strategy**: - Cannot use `formatRelative()` at all - Must implement custom logic - Use `formatInTimeZone()` for time formatting - Build relative strings based on day differences