Get the date data for a certain month and organize it by week

getDaysInWeek.js

function getDaysInWeek(year, month) {
    function getDaysInMonth(year, month) {
      return new Date(year, month, 0).getDate();
    }
    const monthDays = getDaysInMonth(year, month);
    console.log(monthDays);
    let startDate = 1;
    const results = [];
    while (startDate <= monthDays) {
      const week = [0, 0, 0, 0, 0, 0, 0];
      let day = new Date(year, month - 1, startDate).getDay();
      day = day === 0 ? 6 : day - 1;
      week.forEach((item, index) => {
        if (index >= day && startDate <= monthDays) {
          week[index] = startDate;
          startDate++;
        }
      });
      results.push(week);
    }
    return results;
}