MCP Time Server Node

import { getTimezoneOffset } from 'date-fns-tz'; export interface TimeServerConfig { defaultTimezone: string; } let cachedConfig: TimeServerConfig | null = null; /** * Validates if a timezone string is valid */ function isValidTimezone(timezone: string): boolean { try { const offset = getTimezoneOffset(timezone, new Date()); return !isNaN(offset); } catch { return false; } } /** * Gets the system timezone safely */ function getSystemTimezone(): string | null { try { const resolvedOptions = Intl?.DateTimeFormat?.().resolvedOptions(); return resolvedOptions?.timeZone ?? null; } catch { // Ignore errors } return null; } /** * Get the server configuration including default timezone * Precedence: DEFAULT_TIMEZONE env > system timezone > UTC */ export function getConfig(): TimeServerConfig { // Return cached config if available if (cachedConfig) { return cachedConfig; } let defaultTimezone = 'UTC'; // Final fallback // Check DEFAULT_TIMEZONE environment variable const envTimezone = process.env.DEFAULT_TIMEZONE; if (envTimezone && envTimezone !== '' && isValidTimezone(envTimezone)) { defaultTimezone = envTimezone; } else { // Try system timezone (which respects TZ env var) const systemTz = getSystemTimezone(); if (systemTz && isValidTimezone(systemTz)) { defaultTimezone = systemTz; } } // Create and cache the config cachedConfig = Object.freeze({ defaultTimezone, }); return cachedConfig; } /** * Reset the configuration cache (mainly for testing) */ export function resetConfigCache(): void { cachedConfig = null; }