dates.js

const date = new Date(2024, 03, 25);
console.log(date.toLocaleString());
const range = 'month';

/** using native date **/
const generateDates = (date, range = 'month', splitIntoWeeks = true) => {
  // the first day of the month
  let startDate = new Date(
		date.getFullYear(),
		date.getMonth(),
		range === 'month' ? 1 : date.getDate()
	);
  let limit = range === 'month' ? 42 : 7;
  let calendarDays = [];

	for (let day = 0; day < limit; day++) {
    if (day === 0) {
    		const weekdayOfStartDate = startDate.getDay();
        // if weekday of 1st day of the month is not sunday, change start date to the previous sunday before the start date
        startDate.setDate(
        	startDate.getDate() - weekdayOfStartDate
        )
    } else {
    	startDate.setDate(startDate.getDate() + 1);
    }
    
    let calendarDay = {
    	currentMonth: startDate.getMonth() === date.getMonth(),
      date: new Date(startDate).toLocaleString(),
    }
    
    // ignore last week if dates are not the same with the current date month
    if (day === 35 && calendarDay.currentMonth == false) {
      break;
    }

    calendarDays.push(calendarDay);
  }
  
  console.log(calendarDays);
  
  return calendarDays;
};

/** using dayjs **/
dayjs.extend(dayjs_plugin_weekday);
const generateDates2 = (date, range = 'month') => {
	let startDate =  range === 'month' ? dayjs(date).startOf('month') : dayjs(date);
  let limit = range === 'month' ? 42 : 7;
  let calendarDays = [];
  for (let day = 0; day < limit; day++) {
    startDate = day === 0 ? startDate.weekday(0) : startDate.add(1, 'day');

		let calendarDay = {
      currentMonth: startDate.month() === dayjs(date).month(),
      date: startDate.format(),
      year: startDate.year(),
      month: startDate.month(),
      day: startDate.date(),
    };

    // ignore last week if dates are not the same with the current date month
    if (day === 35 && calendarDay.currentMonth == false) {
      break;
    }
    
    calendarDays.push(calendarDay);
  }
  
/*   const calendarDays = [...Array(limit)].map((_, day) => {
      startDate = day === 0 ? startDate.weekday(0) : startDate.add(1, 'day');
       let calendarDay = {
      currentMonth: startDate.month() === dayjs(date).month(),
      date: startDate.format(),
    };
    
    return calendarDay;
  }) */

  return calendarDays;
}

console.log(generateDates2(date, range));