isBusinessDay

Checks whether a date falls on a business day (i.e. not a weekend day).

This is the logical inverse of isWeekend. By default, business days are Monday through Friday. Pass a custom weekendDays to adapt to other calendars.

Note: This helper does not account for public holidays — those are country- and region-specific. Use it in combination with your own holiday list if needed.

Returns false if the input is invalid.

Available since v2.0.0

Import

import { isBusinessDay } from '@helpers4/date';

Signature

isBusinessDay(date: DateLike, weekendDays: readonly WeekDay[]): boolean

Parameters

Parameter	Type	Description
date	DateLike	The date to check
weekendDays	readonly WeekDay[]	Override which days count as weekend (default: [0, 6])

Returns

boolean — true if the date is not a weekend day

Examples

isBusinessDay

isBusinessDay('2025-01-20') // => true  (Monday)
isBusinessDay('2025-01-18') // => false (Saturday)

// UAE weekend (Friday + Saturday)
const uaeWeekend = [WeekDays.Friday, WeekDays.Saturday] as const;
isBusinessDay('2025-01-19', uaeWeekend) // => true  (Sunday = workday)
isBusinessDay('2025-01-17', uaeWeekend) // => false (Friday = weekend)

Related Types

DateLike

A value that can be converted to a Date.

• Date — used as-is (validated for Invalid Date)
• number — treated as a timestamp (seconds or milliseconds, auto-detected); 0 is treated as invalid and produces null in ensureDate
• string — parsed via new Date(string)
• Temporal.Instant | Temporal.ZonedDateTime — read via their epochMilliseconds property

type DateLike = Date | number | string | Temporal.Instant | Temporal.ZonedDateTime

WeekDay

A day-of-week number following the JavaScript Date.getDay() convention: 0 = Sunday, 1 = Monday, … 6 = Saturday.

Prefer using WeekDays named constants for readability: WeekDays.Monday instead of 1.

type WeekDay = (typeof WeekDays)[keyof typeof WeekDays]

Source

View source on GitHub