Calculate previous working day excluding weekends and federal holidays in JavaScript

Question

I am writing a function which will provide me previous working day for any given date. Working day means it is a weekday and there\'s no federal holiday on that day.

My

Answer 1

When you are checking for holidays array you are checking full date instead of the date part.

function check_previous_business_date(date, timezone) {
      const startDate = new Date(luxon.DateTime.fromISO(date).setZone(timezone));
      const todayTimeStamp = +new Date(startDate); // Unix timestamp in milliseconds
      const oneDayTimeStamp = 1000 * 60 * 60 * 24; // Milliseconds in a day
      const diff = todayTimeStamp - oneDayTimeStamp;
      const yesterdayDate = new Date(diff);
      const yesterdayString = yesterdayDate.getFullYear()
         + '-' + (yesterdayDate.getMonth() + 1) + '-' + yesterdayDate.getDate();
      for (startDate.setDate(startDate.getDate() - 1);
        !startDate.getDay() || startDate.getDay() === 6 ||
        federalHolidays.includes(startDate.toISOString().split('T')[0]) ||
        federalHolidays.includes(yesterdayString);
        startDate.setDate(startDate.getDate() - 1)
      ) { 
      }

      return startDate.toISOString().split('T')[0];
    }
const federalHolidays= [
  '2019-05-27',
  '2019-09-02',
  '2019-10-14',
  '2019-11-11'
];
console.log('Prev. day of 2019-05-28 is ',check_previous_business_date('2019-05-28T07:00:00.000Z', 'America/New_York'));
console.log('Prev. day of 2019-06-20 is ',check_previous_business_date('2019-06-20T07:00:00.000Z', 'America/New_York'));