Date Class

Date is Alia's built-in date-time class, used to represent and process date and time data. It is based on UTC time.

Creating a Date

No Arguments (Current Time)

const now = new Date

From a String

const d = new Date ['2024-06-15']
const d2 = new Date ['2024-06-15 14:30:45']

Supported formats: YYYY-MM-DD or YYYY-MM-DD HH:mm:ss

From an Object

const d = new Date [*[year: 2024, month: 6, day: 15, hour: 14, minute: 30, second: 45, millisecond: 500]]

Available fields: year, month, day, hour, minute, second, millisecond

From a Timestamp

const d = new Date [1700000000000]

From an Array

const arr = ['2024-06-15']
const d = new Date [arr]

The first element of the array is a date string or timestamp; that element is parsed as the date.

Instance Properties

All properties are read-only getters:

Property	Type	Description
year	Number	Year (UTC)
month	Number	Month (1-12)
day	Number	Day of month (1-31)
hour	Number	Hour (0-23)
minute	Number	Minute (0-59)
second	Number	Second (0-59)
millisecond	Number	Millisecond (0-999)
weekday	Number	Day of week (1=Sunday, 2=Monday, ..., 7=Saturday)
timestamp	Number	Unix timestamp (milliseconds)

const d = new Date ['2024-06-15 14:30:45']
print d.year        ~ 2024
print d.month       ~ 6
print d.day         ~ 15
print d.hour        ~ 14
print d.minute      ~ 30
print d.second      ~ 45
print d.weekday     ~ 7

Instance Methods

addTime

Returns a new Date with the specified amount of time added.

const d = new Date ['2024-01-10']
const d2 = d.addTime 5 in Date.Days
print d2.day  ~ 15

subTime

Returns a new Date with the specified amount of time subtracted.

const d = new Date ['2024-01-20']
const d2 = d.subTime 5 in Date.Days
print d2.day  ~ 15

diffTime

Computes the difference from another Date and returns a Number.

const d1 = new Date ['2024-01-20']
const d2 = new Date ['2024-01-10']
const diff = d1.diffTime d2 in Date.Days
print diff  ~ 10

toFormat

Formats the Date as a string.

const d = new Date ['2024-01-15 09:05:03']
print d.toFormat 'YYYY-MM-DD'               ~ '2024-01-15'
print d.toFormat 'YYYY/MM/DD HH:mm:ss'     ~ '2024/01/15 09:05:03'
const dMs = new Date [*[year: 2024, month: 1, day: 15, hour: 9, minute: 5, second: 3, millisecond: 123]]
print dMs.toFormat 'HH:mm:ss.SSS'            ~ '09:05:03.123'

isBefore / isAfter / isSame

Compares two Dates.

const d1 = new Date ['2024-01-10']
const d2 = new Date ['2024-01-20']
print d1.isBefore d2  ~ true
print d1.isAfter d2   ~ false
print d1.isSame d1    ~ true

isLeapYear

Checks whether the year is a leap year. Zero-argument methods are invoked via call and return a Boolean.

const d = new Date ['2024-01-01']
print call d.isLeapYear  ~ true

daysInMonth

Gets the number of days in the current month. Zero-argument methods are invoked via call and return a Number.

const d = new Date ['2024-02-01']
print call d.daysInMonth  ~ 29

Time Unit Constants

Constant	Value
Date.Years	'Year'
Date.Months	'Month'
Date.Weeks	'Week'
Date.Days	'Day'
Date.Hours	'Hour'
Date.Minutes	'Minute'
Date.Seconds	'Second'
Date.Milliseconds	'Millisecond'

const d = new Date ['2024-01-10']
const d2 = d.addTime 3 in Date.Months
const diff = d2.diffTime d in Date.Days

Static Methods

Date.now

Gets the current timestamp. Zero-argument methods are invoked via call and return a Number.

const ts = call Date.now

Date.parseDate

Parses a date from a string.

const d = Date.parseDate '2024-06-15'
print d.year  ~ 2024

Date.fromTimestamp

Creates a Date from a timestamp.

const d = Date.fromTimestamp 1700000000000

Date.fromParts

Creates a Date from individual parts. year and month are required keywords; day, hour, minute, second, and millisecond are optional keywords.

const d = Date.fromParts year 2024 month 6 day 15 hour 14 minute 30 second 45

Date.leapYear

Checks whether the specified year is a leap year.

print Date.leapYear 2024  ~ true
print Date.leapYear 2023  ~ false

Date.daysInMonthStatic

Gets the number of days in the specified year and month.

print Date.daysInMonthStatic year 2024 month 2  ~ 29

Format Patterns

Token	Description	Example
YYYY	Four-digit year	2024
MM	Two-digit month	01
DD	Two-digit day	15
HH	Two-digit hour	09
mm	Two-digit minute	05
ss	Two-digit second	03
SSS	Three-digit millisecond	123
WW	Weekday number	2
DDname	Weekday name	Monday
OO	Month name	January