Generate Month Calendar by Luxon

generateMonthCalendar.ts

import { Info, DateTime } from "luxon";

function generateMonthCalendar(dt: DateTime, locale = "en-US") {
  const startOfMonth = dt.startOf("month");

  // Prepare an array to fill in the calendar
  const calendar = [];
  for (let i = 0; i < startOfMonth.weekday - 1; i++) {
    calendar.push("   ");
  }

  if (!dt.daysInMonth) return;

  for (let day = 1; day <= dt.daysInMonth; day++) {
    // Format the day to ensure single-digit days are properly padded
    let dayString =
      day === dt.day
        ? `[${day.toString().padStart(2)}]`
        : day.toString().padStart(3);
    if (
      day === dt.day + 1 &&
      !DateTime.local(dt.year, dt.month, dt.day).isWeekend
    ) {
      dayString = dayString.slice(1);
    }
    calendar.push(dayString);
  }

  // Add padding at the end if needed to complete the final week
  while (calendar.length % 7 !== 0) {
    calendar.push("   ");
  }

  // Generate days of the week headers based on locale
  const daysOfWeek = Info.weekdays("short", { locale });
  const header = daysOfWeek.map((day) => day.padStart(3, " ")).join(" ");

  // Month and year title
  const monthYearTitle = dt.setLocale(locale).toFormat("LLLL yyyy");

  // Print the calendar
  let printedCalendar = monthYearTitle + "\n" + header + "\n";
  for (let i = 0; i < calendar.length; i += 7) {
    printedCalendar += calendar.slice(i, i + 7).join(" ") + "\n";
  }

  return printedCalendar.trim();
}

export default generateMonthCalendar;