Working days

Start dateWorking days to add

2026-08-20

Skips 2 weekend days and 1 holiday: 17 Aug Independence Day.

Runs in your browser.

Working days skip weekends, national holidays, and (by default) collective leave from holiday. Use them for payroll cut-offs, SLAs and due dates.

Functions

Go	TypeScript	Returns
`workday.IsWorkday(date, opts)`	`workday.isWorkday(date, opts?)`	Whether `date` is a working day
`workday.Add(date, days, opts)`	`workday.add(date, days, opts?)`	The date `days` working days later (negative goes back)
`workday.Count(from, to, opts)`	`workday.count(from, to, opts?)`	Working days from `from` to `to`, inclusive

Options

Go `Options`	TypeScript	Default
`Weekend []time.Weekday`	`weekend: number[]`	Saturday and Sunday
`CollectiveLeaveIsWorkday`	`collectiveLeaveIsWorkday`	`false`

TypeScript weekend days use 0 for Sunday to 6 for Saturday, like Date.getUTCDay(). A six-day work week is [0].

Calculations only work inside the years covered by holiday data, so a result is never silently wrong. A date outside that range fails with range.

Errors

date, range (outside the covered years, or from after to), options (an invalid weekend day, or every day of the week as weekend).

package main

import (
  "fmt"
  "time"

  "github.com/haikalmumtaz233/nusaindex/workday"
)

func main() {
  open, err := workday.IsWorkday("2026-08-17", workday.Options{})
  if err == nil {
    fmt.Println(open)
  }

  due, err := workday.Add("2026-08-14", 3, workday.Options{})
  if err == nil {
    fmt.Println(due)
  }

  days, err := workday.Count("2026-08-01", "2026-08-31", workday.Options{})
  if err == nil {
    fmt.Println(days)
  }

  sixDay := workday.Options{Weekend: []time.Weekday{time.Sunday}, CollectiveLeaveIsWorkday: true}
  days, err = workday.Count("2026-08-01", "2026-08-31", sixDay)
  if err == nil {
    fmt.Println(days)
  }
}

import * as workday from "nusaindex/workday";

const open = workday.isWorkday("2026-08-17");
if (open.ok) {
  console.log(open.value);
}

const due = workday.add("2026-08-14", 3);
if (due.ok) {
  console.log(due.value);
}

const days = workday.count("2026-08-01", "2026-08-31");
if (days.ok) {
  console.log(days.value);
}

const sixDay = { weekend: [0], collectiveLeaveIsWorkday: true };
const sixDayCount = workday.count("2026-08-01", "2026-08-31", sixDay);
if (sixDayCount.ok) {
  console.log(sixDayCount.value);
}

false
2026-08-20
19
24