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Adam Shaw edited this page Oct 10, 2011 · 7 revisions

Constructors

new XDate()
Creates a new XDate with the current date and time
new XDate(xdate)
Creates a copy of the given XDate
new XDate(nativeDate)
Creates a new XDate from a native Date
new XDate(milliseconds, hasLocalTimezone)
Creates a new XDate that is milliseconds since the UTC epoch.
new XDate(year, month, date, hours, minutes, seconds, milliseconds,
          hasLocalTimezone)
hasLocalTimezone can be specified even if the previous arguments are not.
new XDate(dateString)
read more about date-string parsing

All new instances are bound to the local timezone, unless hasLocalTimezone has explicitly been set to false.

The constuctors can be called without the new operator, as a function.

Timezones

Just like a native Date, an XDate is represented by its number of milliseconds since the epoch. Also like a native Date, methods like getDate and getHours are dependant upon the client computer's timezone. However, you can remove this reliance on the client's timezone and make a UTC date, a date without a timezone.

A date without a timezone will have all of its "get" methods be identical to its "getUTC" methods, won't experience any daylight-savings time, and won't have timezone information in any of its to-string methods.

.removeLocalTimezone(coerce)
Removes the local timezone and makes a timezone-less UTC date.
.addLocalTimezone(coerce)
Binds the local timezone to the date.
.hasLocalTimezone()
Returns true if the date is bound to the local timezone, false otherwise.
.getTimezoneOffset()
Returns the number of minutes from UTC, just like the native Date's getTimezoneOffset. However, if the XDate has no timezone, 0 will be returned.

If the coerce argument is set to true, the date will have the same year/month/date/etc (via methods like getMinutes, etc) before and after the conversion. However, in order to make this happen, the underlying millisecond time of the date will change. By default, no coercion will happen.

Please note, these methods directly modify the object. Use clone if you need a copy.

Getters

.getFullYear()
Returns the 4-digit year
.getMonth()
Value is zero-index, meaning Jan=0, Feb=1, Mar=2, etc.
.getWeek()
Returns the ISO week of the year
.getDate()
Returns the date of the month
.getDay()
Returns the day-of-week as a number. Sun=0, Mon=1, Tue=2, etc.
.getHours()
.getMinutes()
.getSeconds()
.getMilliseconds()
.getTime()
Milliseconds since the epoch.
.valueOf()
Milliseconds since the epoch. Identical to getTime.

Setters

.setFullYear(year, preventOverflow)
year is a 4-digit year
.setMonth(month, preventOverflow)
month is zero-indexed, meaning Jan=0, Feb=1, Mar=2, etc.
.setDate(date)
Set the date of the month
.setHours(hours)
.setMinutes(minutes)
.setSeconds(seconds)
.setMilliseconds(milliseconds)
Milliseconds since the epoch
.setTime(milliseconds)
Milliseconds since the epoch. Identical to setMilliseconds.

Setting preventOverflow to true prevents a date from "overflowing" into the next month. Example:

d = new XDate(2011, 7, 31); // August 31
d.setMonth(8); // September
d.toString(); // October 1st!!! because there are only 30 says in September

// let's try this with preventOverflow...
d = new XDate(2011, 7, 31); // August 31
d.setMonth(8, true); // September
d.toString(); // September 30!

Setting preventOverflow to true guarantees the date will be in desired month. It is optional and defaults to false.

Adding

The following methods add or subtract time from the XDate:

.addYears(years, preventOverflow)
.addMonths(months, preventOverflow)
.addWeeks(weeks)
.addDays(days)
.addHours(hours)
.addMinutes(minutes)
.addSeconds(seconds)
.addMilliseconds(milliseconds)

If a value is negative, subtraction will occur. Values may be floating-point numbers.

Please note, these methods directly modify the object. Use clone if you need a copy.

Diffing

The following methods return the amount of time that must be added to the XDate in order to arrive at otherDate.

.diffYears(otherDate)
.diffMonths(otherDate)
.diffWeeks(otherDate)
.diffDays(otherDate)
.diffHours(otherDate)
.diffMinutes(otherDate)
.diffSeconds(otherDate)
.diffMilliseconds(otherDate)

otherDate can be an XDate, a native Date, a milliseconds time, or a date-string.

The results will be positive or negative depending on the ordering of the dates:

var thanksgiving = new XDate(2011, 10, 24);
var christmas = new XDate(2011, 11, 25);
thanksgiving.diffDays(christmas); // 31
christmas.diffDays(thanksgiving); // -31

Also, the results can potentially be floating-point numbers:

var jan2011 = new XDate(2011, 0, 1);
var jul2012 = new XDate(2012, 6, 1);
jan2011.diffYears(jul2012); // 1.5

You'll have to do the rounding or flooring yourself.

Parsing

Date-strings must either be in ISO8601 format or IETF format (like "Mon Sep 05 2011 12:30:00 GMT-0700 (PDT)")

ISO8601 is the preferred format. It has special rules for parsing timezones:

  • If there is a timezone like "-07:00", the date will be converted to the client's timezone.
  • If "Z" is specified as the timezone, the date will be parsed as a UTC time and will have the client's timezone.
  • If no timezone is specified, the resulting date will have no timezone (as if removeLocalTimezone had been called).

Examples:

"2011-09-05" will have no timezone
"2011-09-05T12:30:00" will have no timezone
"2011-09-05T12:30:00-07:00" gets converted to the local timezone
"2011-09-05T12:30:00Z" gets converted to the local timezone

Advanced: extending the parser

Formatting

.toString(formatString, settings)
If formatString is not specified, a browser-produced IETF string will be returned. settings can be a name of an available locale or an object that overrides the default locale's settings.
.toUTCString(formatString, settings)
Same as toString but gets its values from the UTC version of the date. Also, will display "Z" as the timezone.
.toISOString(displayOriginalTimezone)
Returns an ISO8601 string. By default, if the date has a timezone, the string will be displayed in UTC. However, if displayOriginalTimezone is true, the date will be displayed in the client's timezone.
.toDateString()
Same as native Date's toDateString
.toTimeString()
Same as native Date's toTimeString
.toLocaleString()
Same as native Date's toLocaleString
.toLocaleDateString()
Same as native Date's toLocaleDateString
.toLocaleTimeString()
Same as native Date's toLocaleTimeString

A formatString can contain any of the following tokens:

fff milliseconds, 3-digits
s seconds
ss seconds, 2-digits
m minutes
mm minutes, 2-digits
h hours, 12-hour clock
hh hours, 12-hour clock, 2-digits
H hours, 24-hour clock
HH hours, 24-hour clock, 2-digits
d date number
dd date number, 2-digits
ddd day name, 3-characters (like "Sun")
dddd day name, full (like "Sunday")
M month number (Jan=1, Feb=2, etc)
MM month number, 2-digits
MMM month name, 3-characters (like "Jan")
MMMM month name, full (like "January")
yy year, 2-digits
yyyy year, 4-digits
t a/p
tt am/pm
T A/P
TT AM/PM
z timezone offset hour (like "-7")
zz timezone offset hour, 2-digits (like "-07")
zzz timezone offset hour, 2-digits, and minutes (like "-07:00")
w ISO week number
ww ISO week number, 2 digits
S day-of-week ordinal (like "st", "nd", "rd")

Example:

var d = new XDate(2012, 5, 8);
d.toString("MMM d, yyyy"); // "Jun 8, 2012"

If you want to have literal text in your formatString, enclose it in single quotes:

var d = new XDate(2012, 5, 8);
d.toString("'the month is' MMMM"); // "the month is June"

A literal single quote is represented by two consecutive single quotes.

If you want to output text only if certain values are non-zero, enclose your tokens in parenthesis:

new XDate(2011, 0, 1, 6, 0).toString('M/d/yy h(:mm)TT'); // "1/1/11 6AM"
new XDate(2011, 0, 1, 6, 30).toString('M/d/yy h(:mm)TT'); // "1/1/11 6:30AM"

Advanced:

Utilities

.clone()
returns a copy of the XDate
.clearTime()
sets the hours, minutes, seconds, and milliseconds to zero
.isValid()
return true if the XDate is a valid date, false otherwise
.toDate()
Returns a native Date conversion of the XDate

The following utilities are members of the XDate class and are not associated with a specific XDate instance:

XDate.getDaysInMonth(year, month)
Returns the number of days in the given month
XDate.parse(dateString)
Parses a date-string and returns milliseconds since the epoch. You'll probably want to use new XDate(dateString) instead.
XDate.now()
Returns the current date, as milliseconds since the epoch
XDate.today()
Returns the current date with time cleared, as an XDate object
XDate.UTC(year, month, date, hours, minutes, seconds, milliseconds)
Returns a milliseconds time since the epoch for the given UTC date

Chaining

Many of XDate's methods return a reference to the same XDate object. This allows you to "chain" operations together and makes for more concise code:

d1 = new XDate();
d2 = d1.clone()
       .removeLocalTimezone()
       .setDate(1)
       .addMonths(1)
       .addYears(2);

Inconsistencies with Native Date

XDate attempts to be "backwards-compatible" with the native Date object. However, there are two small departures that were made:

If you've never noticed, a native Date object returns it's millisecond value every time there is a "set" method. This is not very helpful. In the same situations, an XDate will return a reference to itself to allow for chaining. This is much more useful, but does not match the way the native Date works.

Also, when a native Date is concatenated with a string (with the + operator), the object will produce a date-string. However, this behavior was impossible to emulate with XDate, so please always explicitly use toString before concatenating with a string:

var nativeDate = new Date();
alert("my date: " + nativeDate); // "my date: Mon Sep 05 2011 13:12:23 GMT-0700 (PDT)"

var xdate = new XDate();
alert("my date: " + xdate); // "my date: 1315253543319"  <-- probably not what you wanted!
alert("my date: " + xdate.toString()); // "my date: Mon Sep 05 2011 13:12:23 GMT-0700 (PDT)"

UTC Methods

The following methods are similar to previously mentioned methods but operate on the UTC values of the date:

.getUTCFullYear()
.getUTCMonth()
.getUTCWeek()
.getUTCDate()
.getUTCDay()
.getUTCHours()
.getUTCMinutes()
.getUTCSeconds()
.getUTCMilliseconds()
.setUTCFullYear(year)
.setUTCMonth(month)
.setUTCDate(date)
.setUTCHours(hours)
.setUTCMinutes(minutes)
.setUTCSeconds(seconds)
.setUTCMilliseconds(milliseconds)

Deprecated

The following methods are available, but please don't use them:

.getYear()
.setYear(twoDigitYear)

About

XDate was originally created by Adam Shaw for the FullCalendar project.

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