Documentation Index
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ZEN provides the d() function for comprehensive date handling with timezone support, arithmetic, comparisons, and formatting.
Creating dates
From string
d("2024-01-15") // 2024-01-15T00:00:00Z
d("2024-01-15 14:30") // 2024-01-15T14:30:00Z
d("2024-01-15 14:30:45") // 2024-01-15T14:30:45Z
With timezone
d("2024-01-15", "America/New_York") // 2024-01-15T00:00:00-05:00
d("2024-01-15", "Europe/London") // 2024-01-15T00:00:00Z
d("2024-01-15 14:30", "Asia/Tokyo") // 2024-01-15T14:30:00+09:00
Current date/time
d() // Current date and time
d("America/Los_Angeles") // Current time in LA timezone
Date components
Getters
| Method | Example | Result |
|---|
.year() | d("2024-01-15").year() | 2024 |
.month() | d("2024-01-15").month() | 1 |
.day() | d("2024-01-15").day() | 15 |
.weekday() | d("2024-01-15").weekday() | 1 (Monday) |
.hour() | d("2024-01-15 14:30").hour() | 14 |
.minute() | d("2024-01-15 14:30").minute() | 30 |
.second() | d("2024-01-15 14:30:45").second() | 45 |
.dayOfYear() | d("2024-01-15").dayOfYear() | 15 |
.quarter() | d("2024-01-15").quarter() | 1 |
.timestamp() | d("2024-01-15").timestamp() | 1705276800000 |
Setters
d("2024-01-15").set("year", 2025) // 2025-01-15
d("2024-01-15").set("month", 6) // 2024-06-15
d("2024-01-15").set("day", 20) // 2024-01-20
Date arithmetic
Adding time
d("2024-01-15").add("1d") // 2024-01-16
d("2024-01-15").add("1w") // 2024-01-22
d("2024-01-15").add("1M") // 2024-02-15
d("2024-01-15").add("1y") // 2025-01-15
d("2024-01-15").add("2d 5h") // 2024-01-17T05:00:00
// Alternative syntax
d("2024-01-15").add(1, "d") // 2024-01-16
d("2024-01-15").add(3, "M") // 2024-04-15
Subtracting time
d("2024-01-15").sub("7d") // 2024-01-08
d("2024-01-15").sub("1M") // 2023-12-15
d("2024-01-15").sub(1, "y") // 2023-01-15
Duration units
| Unit | Aliases |
|---|
| Year | y, year, years |
| Month | M, month, months |
| Week | w, week, weeks |
| Day | d, day, days |
| Hour | h, hour, hours |
| Minute | m, minute, minutes |
| Second | s, second, seconds |
Date comparisons
Comparison methods
d("2024-01-15").isBefore(d("2024-01-20")) // true
d("2024-01-15").isAfter(d("2024-01-10")) // true
d("2024-01-15").isSame(d("2024-01-15")) // true
d("2024-01-15").isSameOrBefore(d("2024-01-15")) // true
d("2024-01-15").isSameOrAfter(d("2024-01-15")) // true
Comparison with granularity
d("2024-01-15").isSame(d("2024-01-20"), "month") // true (same month)
d("2024-01-15").isSame(d("2024-06-15"), "year") // true (same year)
d("2024-01-15").isBefore(d("2024-02-01"), "month") // true
Comparison operators
d("2024-01-15") == d("2024-01-15") // true
d("2024-01-15") != d("2024-01-20") // true
d("2024-01-15") < d("2024-01-20") // true
d("2024-01-15") > d("2024-01-10") // true
d("2024-01-15") <= d("2024-01-15") // true
d("2024-01-15") >= d("2024-01-15") // true
Range checks
d("2024-01-15") in [d("2024-01-01")..d("2024-01-31")] // true
d("2024-01-15") in (d("2024-01-01")..d("2024-01-31")) // true
d("2024-02-15") not in [d("2024-01-01")..d("2024-01-31")] // true
Calculating differences
d("2024-01-15").diff("2024-01-10", "day") // 5
d("2024-01-15").diff("2024-01-01", "week") // 2
d("2024-06-15").diff("2024-01-15", "month") // 5
d("2025-01-15").diff("2024-01-15", "year") // 1
d("2024-01-10").diff("2024-01-15", "day") // -5
Start and end of periods
d("2024-01-15").startOf("day") // 2024-01-15T00:00:00
d("2024-01-15").endOf("day") // 2024-01-15T23:59:59
d("2024-01-15").startOf("month") // 2024-01-01T00:00:00
d("2024-01-15").endOf("month") // 2024-01-31T23:59:59
d("2024-01-15").startOf("year") // 2024-01-01T00:00:00
d("2024-01-15").endOf("year") // 2024-12-31T23:59:59
d("2024-01-15").startOf("week") // 2024-01-15T00:00:00 (Monday)
d("2024-01-15").endOf("week") // 2024-01-21T23:59:59 (Sunday)
d("2024-05-15").startOf("quarter") // 2024-04-01T00:00:00
d("2024-05-15").endOf("quarter") // 2024-06-30T23:59:59
Timezone conversion
d("2024-01-15T12:00:00Z").tz("America/New_York") // 2024-01-15T07:00:00-05:00
d("2024-01-15T12:00:00Z").tz("Europe/London") // 2024-01-15T12:00:00Z
d("2024-01-15T12:00:00Z").tz("Asia/Tokyo") // 2024-01-15T21:00:00+09:00
d("2024-01-15", "America/New_York").offsetName() // "America/New_York"
Relative dates
d().isToday() // true if today
d().sub(1, "d").isYesterday() // true
d().add(1, "d").isTomorrow() // true
Validation
d("2024-01-15").isValid() // true
d("invalid").isValid() // false
d("2024-02-30").isValid() // false (invalid date)
d(null).isValid() // false
Leap years
d("2024-01-15").isLeapYear() // true
d("2023-01-15").isLeapYear() // false
d("2000-01-15").isLeapYear() // true
d("1900-01-15").isLeapYear() // false
d("2024-01-15").format("%Y-%m-%d") // "2024-01-15"
d("2024-01-15").format("%Y/%m/%d") // "2024/01/15"
d("2024-01-15T14:30:45Z").format("%A, %B %d %Y") // "Monday, January 15 2024"
d("2024-01-15T14:30:45Z").format("%H:%M:%S") // "14:30:45"
| Code | Description | Example |
|---|
%Y | 4-digit year | 2024 |
%m | Month (01-12) | 01 |
%d | Day (01-31) | 15 |
%H | Hour (00-23) | 14 |
%M | Minute (00-59) | 30 |
%S | Second (00-59) | 45 |
%A | Full weekday | Monday |
%a | Abbreviated weekday | Mon |
%B | Full month | January |
%b | Abbreviated month | Jan |
%j | Day of year | 015 |
Min/max with dates
min([d("2024-01-15"), d("2024-03-20"), d("2024-02-10")]) // 2024-01-15
max([d("2024-01-15"), d("2024-03-20"), d("2024-02-10")]) // 2024-03-20
Common patterns
Age calculation
d().diff(birthDate, "year")
Days until expiration
d(expirationDate).diff(d(), "day")
Is within last 30 days
d(eventDate).isAfter(d().sub(30, "d"))
Business days check
d(orderDate).weekday() in [1..5] // 1=Monday, 5=Friday
