/**
* dateUtils.ts
* Shared date calculation utilities
*/
/**
* Creates a date object representing the start of today (midnight)
*/
export function getTodayStart(): Date {
const now = new Date();
return new Date(now.getFullYear(), now.getMonth(), now.getDate());
}
/**
* Creates a date object representing the start of tomorrow (midnight)
*/
export function getTomorrowStart(): Date {
const today = getTodayStart();
const tomorrow = new Date(today);
tomorrow.setDate(tomorrow.getDate() + 1);
return tomorrow;
}
/**
* Gets the first day of the week for the current locale using Intl.Locale API.
* @returns 0-6 where 0=Sunday, 1=Monday, ..., 6=Saturday
*/
function getLocaleFirstDay(): number {
try {
// Get the default locale from the system
const defaultLocale =
Intl.DateTimeFormat().resolvedOptions().locale || 'en-US';
const locale = new Intl.Locale(defaultLocale);
const weekInfo = (
locale as Intl.Locale & { weekInfo?: { firstDay?: number } }
).weekInfo;
if (weekInfo?.firstDay !== undefined) {
// Intl returns 1-7 where 1=Monday, 7=Sunday
// Convert to JS format 0-6 where 0=Sunday
return weekInfo.firstDay === 7 ? 0 : weekInfo.firstDay;
}
} catch {
// Fallback to Sunday if Intl.Locale is unavailable
}
return 0; // Default: Sunday
}
/**
* Creates a date object representing the start of the current calendar week.
* Uses Intl.Locale.weekInfo for locale-aware week start when available.
* Falls back to Sunday for environments without Intl.Locale support.
*/
export function getWeekStart(): Date {
const today = getTodayStart();
const dayOfWeek = today.getDay(); // 0=Sunday, 6=Saturday
const firstDay = getLocaleFirstDay();
const weekStart = new Date(today);
weekStart.setDate(today.getDate() - ((dayOfWeek - firstDay + 7) % 7));
return weekStart;
}
/**
* Creates a date object representing the end of the current calendar week
* (start of next week). Matches Swift's Calendar.current.dateInterval(of: .weekOfYear).
*/
export function getWeekEnd(): Date {
const weekStart = getWeekStart();
const weekEnd = new Date(weekStart);
weekEnd.setDate(weekStart.getDate() + 7);
return weekEnd;
}
/**
* Creates a date object representing the start of a specific date (midnight)
*/
export function getDateStart(date: Date): Date {
return new Date(date.getFullYear(), date.getMonth(), date.getDate());
}
