Date Pattern helpers

match-iz 🔥 docs

Date Pattern-helpers

• Time
• Days of the week
• Weeks of the month
• Months
• Years

The following date matchers are available from match-iz/dates (or directly from the matchiz and matchiz.utc global variables if you're using the browser-build.)

Time	Days of the week	Weeks of the month	Months	Years
isHour(0..23)	isDay(-31..31)	nthSun(-5..5)	isMonth(1..12)	isYear(n)
isMinute(0..59)	isDayOfWeek(0..6)	nthMon(-5..5)	-	isWeekNumber(1..52)
isSecond(0..59)	-	nthTue(-5..5)	isJan	isLeapYear
-	isSun	nthWed(-5..5)	isFeb	-
isAM	isMon	nthThu(-5..5)	isMar	-
isPM	isTue	nthFri(-5..5)	isApr	-
isMorning	isWed	nthSat(-5..5)	isMay	-
isAfternoon	isThu	-	isJun	-
isEvening	isFri	-	isJul	-
-	isSat	-	isAug	-
isBefore(date)	-	-	isSep	-
isAfter(date)	-	-	isOct	-
-	-	-	isNov	-
inThePast(n,timeFrame)	-	-	isDec	-
inTheNext(n,timeFrame)	-	-	-	-
inTheFuture(n,timeFrame)	-	-	-	-
-	-	-	-	-
isTime(ms)	-	-	-	-
-	-	-	-	-
inDay/s(Date)	-	-	-	-
inMonth/s(Date)	-	-	-	-
inYear/s(Date)	-	-	-	-

import { isSun, ...etc } from 'match-iz/dates'
import { isSun, ...etc } from 'match-iz/dates/utc'

---

Time

Matchers	Meaning
isTime	ms since Unix epoch

match(new Date())(
  when(isTime(0), '1st of January 1970'),
  when(isTime(inRange(+new Date(1990), +new Date(2020))), '30 year span'),
  when(
    isTime(ms => ms < 0),
    'Before the 1st of January 1970'
  ),
)

Matchers	Meaning
inDay / inMonth / inYear / inDays / inMonths / inYears	falls within the specified day(s), month(s), or year(s)

let date = new Date(2021, 0, 1, 12, 0, 0)
match(date)(
  when(inDay(new Date(2021, 0, 1)), 'January 1st 2021'),
  when(inDay(new Date(2021, 0, 2)), 'January 2nd 2021')
)

Use a 1-based month index by passing an array:

let date = new Date(2021, 0, 1, 12, 0, 0)
match(date)(
  when(inDay([2021, 1, 1]), 'January 1st 2021'),
  when(inDay([2021, 1, 2]), 'January 2nd 2021')
)

The plural helpers accept arrays of date-objects and/or 1-based month-index arrays:

let date = new Date(2021, 0, 1, 12, 0, 0)
match(date)(
  when(inDays([[2021, 1, 1], new Date(2021, 0, 2)]), 'January 1st or 2nd 2021')
)

Matchers	Meaning
inThePast / inTheNext / inTheFuture	in a past or future time-frame (inTheNext + inTheFuture are the same functions)

match(new Date())(
  when(inThePast(1, 'day'), 'Pretty recent'),
  when(inThePast(2, 'weeks'), 'Last fortnight'),
  when(inTheNext(24, 'hours'), 'Too soon'),
  when(inTheFuture(), "It's coming"),
  when(inThePast(), 'That was quick')
)

// Available time-frames:
// 'ms', 'seconds', 'minutes', 'hours', 'days', 'weeks', 'months', 'years'

Matchers	Meaning
isHour / isMinute / isSecond / isAM / isPM / isMorning / isAfternoon / isEvening	the time of day

const isMidday = allOf(isHour(12), isPM)

match(new Date())(
  when(isHour(0), 'around midnight'),
  when(isHour(inRange(12, 14)), 'lunchtime'),
  when(allOf(isHour(17), isMinute(0), isSecond(0)), 'clock-off'),
  when(isAM, 'morning'),
  when(isPM, 'afternoon'),
  when(isAfternoon, 'afternoon'),
  when(isEvening, 'evening, 6pm-midnight'),
  when(isMidday, "It's midday")
)

Matchers	Meaning
isBefore / isAfter	before/after a date

match(new Date())(
  when(isBefore([2001, 1, 1]), 'Before midnight January 1st, 2001'),
  when(isAfter([1970, 5]), 'After May 1970 (ie; June onwards)'),
  when(isBefore([1999]), 'Before 1999 (ie; up to and including 1998)'),
  when(isAfter(new Date(2001, 0, 1)), 'After midnight January 1st, 2001')
)

---

Days of the week

Matchers	Meaning
isDay / isDayOfWeek / isSun / isMon / isTue / isWed / isThu / isFri / isSat	is that particular day of the month, week, or weekday. isDay accepts negative numbers to work backwards from the end of the month

match(new Date())(
  when(isDay(1), 'First day of the month'),
  when(isDay(-1), 'Last day of the month'),
  when(isMon, "I don't like them"),
  when(anyOf(isSat, isSun), 'Weekend!'),
  when(isDayOfWeek(0), 'Sunday'),
  when(isDayOfWeek(6), 'Saturday'),
  otherwise('Back to the grind')
)

---

Weeks of the month

Matchers	Meaning
nthSun / nthMon / nthTue / nthWed / nthThu / nthFri / nthSat	the nth *day of the month. Negatives allowed to search from the end

match(new Date())(
  when(nthSun(2), 'Second Sunday of the month'),
  when(nthFri(-1), 'Last Friday of the month'),
  when(anyOf(nthMon(1), nthFri(1)), '1st Monday/Friday of the month')
)

---

Months

Matchers	Meaning
isMonth / isJan / isFeb / isMar / isApr / isMay / isJun / isJul / isAug / isSep / isOct / isNov / isDec	is that particular month

match(new Date())(
  when(isJan, "It's January"),
  when(anyOf(isFeb, isMar), 'Is it February or March?'),
  when(allOf(isDec, isDay(24)), 'Christmas already?'),
  when(isMonth(1), "It's January, of course"),
  when(
    isMonth(x => [4, 5].includes(x)),
    dateObj => `April or May: ${dateObj.toString()}`
  )
)

---

Years

Matchers	Meaning
isYear / isWeekNumber / isLeapYear	is the specified year, week-number, or tests if the year is a leap-year

match(new Date())(
  when(isYear(2015), 'Flying cars and skateboards'),
  when(isLeapYear, 'Leap year'),
  when(
    isYear(x => x % 2 === 0),
    dateObj => `An even numbered year: ${dateObj.toString()}`
  ),
  when(allOf(isYear(2020), isMar), 'Better forgotten'),
  when(isWeekNumber(1), 'First week of the year'),
  when(isWeekNumber(52), 'Last week of the year'),
  when(not(isWeekNumber(13)), () => {
    return 'Not the 13th week of the year'
  })
)