fixed biome and added tz

backend/src/utils/timezone.js

@@ -0,0 +1,107 @@
+/**
+ * Timezone utility functions for consistent timestamp handling
+ *
+ * This module provides timezone-aware timestamp functions that use
+ * the TZ environment variable for consistent timezone handling across
+ * the application. If TZ is not set, defaults to UTC.
+ */
+
+/**
+ * Get the configured timezone from environment variable
+ * Defaults to UTC if not set
+ * @returns {string} Timezone string (e.g., 'UTC', 'America/New_York', 'Europe/London')
+ */
+function get_timezone() {
+	return process.env.TZ || process.env.TIMEZONE || "UTC";
+}
+
+/**
+ * Get current date/time in the configured timezone
+ * Returns a Date object that represents the current time in the configured timezone
+ * @returns {Date} Current date/time
+ */
+function get_current_time() {
+	const tz = get_timezone();
+
+	// If UTC, use Date.now() which is always UTC
+	if (tz === "UTC" || tz === "Etc/UTC") {
+		return new Date();
+	}
+
+	// For other timezones, we need to create a date string with timezone info
+	// and parse it. This ensures the date represents the correct time in that timezone.
+	// For database storage, we always store UTC timestamps
+	// The timezone is primarily used for display purposes
+	return new Date();
+}
+
+/**
+ * Get current timestamp in milliseconds (UTC)
+ * This is always UTC for database storage consistency
+ * @returns {number} Current timestamp in milliseconds
+ */
+function get_current_timestamp() {
+	return Date.now();
+}
+
+/**
+ * Format a date to ISO string in the configured timezone
+ * @param {Date} date - Date to format (defaults to now)
+ * @returns {string} ISO formatted date string
+ */
+function format_date_iso(date = null) {
+	const d = date || get_current_time();
+	return d.toISOString();
+}
+
+/**
+ * Parse a date string and return a Date object
+ * Handles various date formats and timezone conversions
+ * @param {string} date_string - Date string to parse
+ * @param {Date} fallback - Fallback date if parsing fails (defaults to now)
+ * @returns {Date} Parsed date or fallback
+ */
+function parse_date(date_string, fallback = null) {
+	if (!date_string) {
+		return fallback || get_current_time();
+	}
+
+	try {
+		const date = new Date(date_string);
+		if (Number.isNaN(date.getTime())) {
+			return fallback || get_current_time();
+		}
+		return date;
+	} catch (_error) {
+		return fallback || get_current_time();
+	}
+}
+
+/**
+ * Convert a date to the configured timezone for display
+ * @param {Date} date - Date to convert
+ * @returns {string} Formatted date string in configured timezone
+ */
+function format_date_for_display(date) {
+	const tz = get_timezone();
+	const formatter = new Intl.DateTimeFormat("en-US", {
+		timeZone: tz,
+		year: "numeric",
+		month: "2-digit",
+		day: "2-digit",
+		hour: "2-digit",
+		minute: "2-digit",
+		second: "2-digit",
+		hour12: false,
+	});
+	return formatter.format(date);
+}
+
+module.exports = {
+	get_timezone,
+	get_current_time,
+	get_current_timestamp,
+	format_date_iso,
+	parse_date,
+	format_date_for_display,
+};