Business Day Logic

Overview

date-wiz has first-class business day support with no plugins required. All functions skip weekends automatically and accept a holidays array of ISO date strings for public holiday exclusion.

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SLA deadline calculation

import { addBusinessDays, format } from 'date-wiz';

const ticketOpened = new Date(); // now

// 5-business-day SLA
const deadline = addBusinessDays(ticketOpened, 5, {
  holidays: ['2026-04-03', '2026-04-06'], // Good Friday, Easter Monday
});

console.log(format(deadline, 'LLL'));
// → "March 23, 2026 at ..."

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Working hours SLA check

import { isWithinWorkingHours } from 'date-wiz';

function isSLAClock(date: Date): boolean {
  return isWithinWorkingHours(date, {
    start: '09:00',
    end: '18:00',
    workDays: [1, 2, 3, 4, 5], // Mon–Fri
  });
}

// Only count SLA time during business hours
if (isSLAClock(new Date())) {
  startSLATimer();
}

---

Counting business days between dates

import { countBusinessDays } from 'date-wiz';

const start = new Date('2026-03-09'); // Monday
const end   = new Date('2026-03-20'); // Friday next week

countBusinessDays(start, end)                     // → 9
countBusinessDays(start, end, {
  holidays: ['2026-03-17'],                        // St. Patrick's Day
})                                                 // → 8

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Scheduling recurring reminders

import { addBusinessDays, format } from 'date-wiz';

function getReminders(start: Date, count: number, holidays: string[]) {
  return Array.from({ length: count }, (_, i) =>
    addBusinessDays(start, i + 1, { holidays }),
  );
}

const reminders = getReminders(new Date(), 5, ['2026-04-03']);
reminders.forEach(d => console.log(format(d, 'ddd DD MMM')));
// Mon 16 Mar
// Tue 17 Mar
// Wed 18 Mar
// Thu 19 Mar
// Fri 20 Mar

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Is today a working day?

import { checkIsBusinessDay } from 'date-wiz';

const publicHolidays = ['2026-12-25', '2026-01-01', '2026-08-15'];

if (checkIsBusinessDay(new Date(), { holidays: publicHolidays })) {
  console.log('SLA clock is running');
} else {
  console.log('Weekend or holiday — SLA paused');
}

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Non-standard work weeks

Some regions use a Sunday–Thursday or Saturday–Thursday work week. Pass custom workDays to isWithinWorkingHours:

// Middle East: Sun–Thu
isWithinWorkingHours(new Date(), {
  workDays: [0, 1, 2, 3, 4], // 0=Sun … 4=Thu
  start: '08:00',
  end: '17:00',
})