isWeekend

Check if a period falls on a weekend (Saturday or Sunday).

Signature

function isWeekend(period: Period): boolean

Parameters

• period - Period - The period to check

Returns

boolean - True if the period's reference date is Saturday (6) or Sunday (0)

Description

The isWeekend function checks if a period's reference date falls on a weekend. It uses the JavaScript convention where Sunday is 0 and Saturday is 6.

Examples

Basic Usage

import { period, isWeekend } from '@allystudio/usetemporal/operations'
import { createNativeAdapter } from '@allystudio/usetemporal/native'

const adapter = createNativeAdapter()

// Check specific dates
const friday = period(adapter, new Date('2024-03-15'), 'day')
const saturday = period(adapter, new Date('2024-03-16'), 'day')
const sunday = period(adapter, new Date('2024-03-17'), 'day')

console.log(isWeekend(friday))   // false
console.log(isWeekend(saturday)) // true
console.log(isWeekend(sunday))   // true

Calendar Styling

// Style weekend days differently
function DayCell({ day }) {
  return (
    <div className={`day-cell ${isWeekend(day) ? 'weekend' : 'weekday'}`}>
      <span className="day-number">{day.date.getDate()}</span>
    </div>
  )
}

// CSS
.day-cell.weekend {
  background-color: #f0f0f0;
  color: #666;
}

Filtering Business Days

import { period, divide, isWeekend } from '@allystudio/usetemporal/operations'
import { createNativeAdapter } from '@allystudio/usetemporal/native'

const adapter = createNativeAdapter()

// Get only business days from a month
const month = period(adapter, new Date(), 'month')
const days = divide(adapter, month, 'day')

const businessDays = days.filter(day => !isWeekend(day))
console.log(`${businessDays.length} business days this month`)

Common Patterns

Weekend Counter

import { period, divide, isWeekend } from '@allystudio/usetemporal/operations'
import type { Period, Adapter } from '@allystudio/usetemporal'

// Count weekends in a period
function countWeekends(p: Period, adapter: Adapter): number {
  const days = divide(adapter, p, 'day')
  return days.filter(isWeekend).length
}

// Usage
import { createNativeAdapter } from '@allystudio/usetemporal/native'
const adapter = createNativeAdapter()
const year = period(adapter, new Date(), 'year')
const weekendDays = countWeekends(year, adapter)
console.log(`${weekendDays} weekend days this year`)

Combined with Other Checks

import { isWeekend, isToday } from '@allystudio/usetemporal/operations'
import type { Period, Adapter } from '@allystudio/usetemporal'

function getDayStatus(day: Period, adapter: Adapter) {
  const now = new Date()

  return {
    isWeekend: isWeekend(day),
    isToday: isToday(adapter, now, day),
    isAvailable: !isWeekend(day) && day.start.getTime() > now.getTime()
  }
}

Calendar Grid Generation

import { divide, isWeekend, isSame } from '@allystudio/usetemporal/operations'
import type { Period, Adapter } from '@allystudio/usetemporal'

// Generate calendar grid with weekend information
function generateCalendarGrid(month: Period, adapter: Adapter) {
  const days = divide(adapter, month, 'day')

  return days.map(day => ({
    date: day.date,
    dayNumber: day.date.getDate(),
    isWeekend: isWeekend(day),
    isCurrentMonth: isSame(adapter, day, month, 'month')
  }))
}

Cultural Considerations

The function uses the Western convention where weekends are Saturday and Sunday. Different cultures may have different weekend days:

// Custom weekend checker for different cultures
function isWeekendCustom(period: Period, weekendDays: number[]): boolean {
  return weekendDays.includes(period.date.getDay())
}

// Examples:
// Middle East (Friday-Saturday)
const isMiddleEastWeekend = (day: Period) => 
  isWeekendCustom(day, [5, 6])

// Some banks (Sunday only)
const isBankWeekend = (day: Period) => 
  isWeekendCustom(day, [0])

Performance

The function is very efficient as it only checks the day of week from the period's reference date:

// Implementation
export function isWeekend(period: Period): boolean {
  const day = period.date.getDay()
  return day === 0 || day === 6
}

Usage with Different Period Types

While typically used with day periods, isWeekend works with any period type by checking its reference date:

import { period, isWeekend } from '@allystudio/usetemporal/operations'
import { createNativeAdapter } from '@allystudio/usetemporal/native'

const adapter = createNativeAdapter()

const hourPeriod = period(adapter, new Date('2024-03-16T14:00:00'), 'hour')
console.log(isWeekend(hourPeriod)) // true (Saturday)

const monthPeriod = period(adapter, new Date('2024-03-16'), 'month')
console.log(isWeekend(monthPeriod)) // true (reference date is Saturday)

See Also

• isWeekday - Check for weekdays
• isToday - Check if period is today
• Period Type - Period interface