import * as chrono from 'chrono-node';
/**
* Parse natural language date/time string into a Date object
* Examples: "tomorrow at 3pm", "next Friday", "in 2 hours", "Jan 15 at 10:30am"
* @param input - Natural language date/time string
* @param referenceDate - Optional reference date for relative dates (defaults to now)
* @returns Parsed Date object
* @throws Error if the input cannot be parsed
*/
export function parseDateTime(input: string, referenceDate?: Date): Date {
const parsed = chrono.parseDate(input, referenceDate);
if (!parsed) {
throw new Error(`Could not parse date: "${input}"`);
}
return parsed;
}
/**
* Parse a date range from natural language
* @param startInput - Start date string
* @param endInput - End date string (optional)
* @param defaultDuration - Default duration in milliseconds if end not specified
* @returns Object with start and end dates
*/
export function parseDateRange(
startInput: string,
endInput?: string,
defaultDuration: number = 60 * 60 * 1000 // 1 hour default
): { start: Date; end: Date } {
const start = parseDateTime(startInput);
const end = endInput
? parseDateTime(endInput, start)
: new Date(start.getTime() + defaultDuration);
if (end <= start) {
throw new Error('End date must be after start date');
}
return { start, end };
}
/**
* Format a date for human-readable display
* @param date - Date to format
* @returns Formatted string
*/
export function formatDate(date: Date): string {
return date.toLocaleString('en-US', {
weekday: 'short',
year: 'numeric',
month: 'short',
day: 'numeric',
hour: 'numeric',
minute: '2-digit',
hour12: true
});
}
/**
* Get a date range for common time periods
* @param period - 'today', 'tomorrow', 'this_week', 'next_week', 'this_month'
* @returns Object with start and end dates
*/
export function getCommonDateRange(period: string): { start: Date; end: Date } {
const now = new Date();
const start = new Date(now);
const end = new Date(now);
start.setHours(0, 0, 0, 0);
end.setHours(23, 59, 59, 999);
switch (period.toLowerCase()) {
case 'today':
// Already set correctly
break;
case 'tomorrow':
start.setDate(start.getDate() + 1);
end.setDate(end.getDate() + 1);
break;
case 'this_week': {
const dayOfWeek = start.getDay();
start.setDate(start.getDate() - dayOfWeek); // Sunday
end.setDate(start.getDate() + 6); // Saturday
break;
}
case 'next_week': {
const dayOfWeek = start.getDay();
start.setDate(start.getDate() - dayOfWeek + 7); // Next Sunday
end.setDate(start.getDate() + 6); // Next Saturday
break;
}
case 'this_month':
start.setDate(1); // First day of month
end.setMonth(end.getMonth() + 1, 0); // Last day of month
break;
case 'next_month':
start.setMonth(start.getMonth() + 1, 1); // First day of next month
end.setMonth(end.getMonth() + 2, 0); // Last day of next month
break;
default:
throw new Error(`Unknown period: ${period}`);
}
return { start, end };
}
