isBusinessDay

Signature

isBusinessDay(value: string): boolean

import { isBusinessDay } from "@northguild/gmt/plain/compare";

Return true when value falls on a Monday–Friday ISO business day.

• Uses the fixed ISO Monday–Friday business-day boundary (Mon=1 … Fri=5), matching the definition used by addBusinessDays/subtractBusinessDays.
• Locale-agnostic: no Intl.Locale lookup and no holiday calendar.
• Returns false if value is invalid. This is the locale-agnostic complement to the locale-aware isWeekend: isWeekend resolves weekend days per locale via Intl.Locale.prototype.weekInfo, whereas isBusinessDay always treats Monday–Friday as business days regardless of locale.

Parameters

Parameter	Type	Description
value	string	ISO PlainDate string

Returns

true if value is a Monday–Friday business day, false on invalid input

Examples

isBusinessDay("2024-02-05") // true (Monday)
isBusinessDay("2024-02-10") // false (Saturday)
isBusinessDay("2024-02-04") // false (Sunday)
isBusinessDay("invalid") // false

Source

plain/compare/isBusinessDay.ts