/**
* Date utilities for the activity panel and other viewer components.
* Uses native APIs - no external dependencies.
*/
export const MS_PER_DAY = 86400000;
/**
* Format a Date as YYYY-MM-DD in local timezone.
* Returns null for invalid dates.
*/
export function getLocalDateKey(date: Date): string | null {
try {
if (!(date instanceof Date) || isNaN(date.getTime())) {
return null;
}
const year = date.getFullYear();
const month = String(date.getMonth() + 1).padStart(2, '0');
const day = String(date.getDate()).padStart(2, '0');
return `${year}-${month}-${day}`;
} catch {
return null;
}
}
/**
* Get today's date key in local timezone.
* Returns empty string if date formatting fails (should never happen).
*/
export function getTodayKey(): string {
return getLocalDateKey(new Date()) ?? '';
}
/**
* Get yesterday's date key in local timezone.
* Returns empty string if date formatting fails (should never happen).
*/
export function getYesterdayKey(): string {
return getLocalDateKey(new Date(Date.now() - MS_PER_DAY)) ?? '';
}
/**
* Parse a YYYY-MM-DD date key into a Date object at noon local time.
* Using noon avoids DST edge cases at midnight.
* Returns null for invalid input.
*/
export function parseLocalDate(dateKey: string): Date | null {
try {
if (!/^\d{4}-\d{2}-\d{2}$/.test(dateKey)) {
return null;
}
const date = new Date(dateKey + 'T12:00:00');
if (isNaN(date.getTime())) {
return null;
}
return date;
} catch {
return null;
}
}
/**
* Add days to a date key. Negative values subtract days.
* Returns null for invalid input.
*/
export function addDays(dateKey: string, days: number): string | null {
const date = parseLocalDate(dateKey);
if (!date) return null;
date.setDate(date.getDate() + days);
return getLocalDateKey(date);
}
export interface FormatOptions {
/** Use short format (e.g., "Jan 5") instead of full format */
short?: boolean;
}
/**
* Format a date key as a human-readable label.
* Returns "Today", "Yesterday", or a formatted date string.
*/
export function formatRelativeDay(dateKey: string, options?: FormatOptions): string {
const today = getTodayKey();
const yesterday = getYesterdayKey();
if (dateKey === today) return 'Today';
if (dateKey === yesterday) return 'Yesterday';
const date = parseLocalDate(dateKey);
if (!date) return dateKey; // Fallback to raw key if invalid
if (options?.short) {
return date.toLocaleDateString(undefined, { month: 'short', day: 'numeric' });
}
return date.toLocaleDateString(undefined, {
weekday: 'long',
month: 'long',
day: 'numeric',
year: 'numeric'
});
}
/**
* Format a timestamp as time string (e.g., "2:30 PM").
*/
export function formatTime(date: Date): string {
try {
return date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' });
} catch {
return '';
}
}
/**
* Format a timestamp as short date + time (e.g., "Jan 5, 2:30 PM").
*/
export function formatDateTime(date: Date): string {
try {
const dateStr = date.toLocaleDateString(undefined, { month: 'short', day: 'numeric' });
const timeStr = formatTime(date);
return `${dateStr}, ${timeStr}`;
} catch {
return '';
}
}
/**
* Check if a date is today.
*/
export function isToday(date: Date): boolean {
return getLocalDateKey(date) === getTodayKey();
}
/**
* Check if a date is yesterday.
*/
export function isYesterday(date: Date): boolean {
return getLocalDateKey(date) === getYesterdayKey();
}
