30-seconds-of-code/snippets/addWeekDays.md

title, tags

title	tags
addWeekDays	array,date,intermediate

Returns a date after adding given number of business days.

• Use Array.from() to construct an array with length equal to the businessDayCount.
• Use Array.prototype.reduce() to iterate over the array, and increment startDate using Date.getDate() and Date.setDate().
• If startDate falls on a weekend, update it again by adding either one day or two days to make it a weekday.

const addWeekDays = (startDate, businessDayCount) => 
  Array
    .from({ length: businessDayCount })
    .reduce(date => {
      date = new Date(date.setDate(date.getDate() + 1));
      if (date.getDay() % 6 === 0)
        date = new Date(date.setDate(date.getDate() + ((date.getDay() / 6) + 1)));
        return date;
      }, startDate);

addWeekDays(new Date("Oct 09, 2020"), 5); // 'Oct 16, 2020'
addWeekDays(new Date("Oct 12, 2020"), 5); // 'Oct 19, 2020'