[Javascript] 轻量级的JavaScript日期处理类库xDate使用指南

XDate是一个请谅解的JavaScript的原生Date对象的封装库，提供增强的功能解析，格式化和日期处理。使用起来就和JavaScript自己的对象和方法一样，非常简单。

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xdate.js

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Version: 0.8

Released: Mar 30th, 2013

Development Version

Project on Github

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Dual-licensed under MIT or GPL

使用说明：

　首先在页面中添加 XDate 的 JS 文件

　　之后就可以了 new 一个日期出来，如

var d = new XDate("2012-9-9");
var c = new XDate(2012, 7, 8);
d.addDays(10);
var a = d.toString("yyyy/MM/dd");

Constructors

new XDate()

使用当前的日期和时间创建一个新的XDate

new XDate(xdate)

创建一个新的XDate从一个xdate对象

new XDate(nativeDate)

创建一个新的XDate从一个指定的日期

new XDate(milliseconds)

通过UTC毫秒数创建一个新的XDate。

new XDate(year, month, date, hours, minutes, seconds, milliseconds)

new XDate(dateString)

Getters

.getFullYear(): Returns the 4-digit year (ex: 2012)
.getMonth(): Returns the month of the year. (0-11)
Value is zero-index, meaning Jan=0, Feb=1, Mar=2, etc.
.getWeek(): Returns the ISO week number of the year. (1-53)
.getDate(): Returns the date of the month. (1-31)
.getDay(): Returns the day-of-week as a number. (0-6)
Sun=0, Mon=1, Tue=2, etc.
.getHours(): Returns the hour of the day. (0-23)
.getMinutes(): Returns the minute of the hour. (0-59)
.getSeconds(): Returns the second of the minute. (0-59)
.getMilliseconds(): Returns the millisecond of the second. (0-999)
.getTime(): Returns the number of milliseconds since the epoch.
.valueOf(): Returns the number of 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.
.setWeek(week, year): Moves the xdate to the Monday of the given week with time 00:00:00. The week is represented by a given ISO week number and an optional year. Ifyear is omitted, the xdate's year with be used.
.setDate(date): Sets the date of the month. (1-31)
.setHours(hours): Sets the hour of the day. (0-23)
.setMinutes(minutes): Sets the minute of the hour. (0-59)
.setSeconds(seconds): Sets the second of the minute. (0-59)
.setMilliseconds(milliseconds): Sets the millisecond of the second. (0-999)
.setTime(milliseconds): Sets the number of milliseconds since the epoch.

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

d=newXDate(2011,7,31);// August 31d.setMonth(8);// Septemberd.toString();// October 1st!!! because there are only 30 says in September// let's try this with preventOverflow...d=newXDate(2011,7,31);// August 31d.setMonth(8,true);// Septemberd.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:

varthanksgiving=newXDate(2011,10,24);varchristmas=newXDate(2011,11,25);thanksgiving.diffDays(christmas);// 31christmas.diffDays(thanksgiving);// -31

Also, the result can potentially be a floating-point number:

varjan2011=newXDate(2011,0,1);varjul2012=newXDate(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. Examples:

"2011-09-05"
"2011-09-05T12:30:00"
"2011-09-05T12:30:00-07:00"
"2011-09-05T12:30:00Z"

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. As a result, "Z" will be displayed as the timezone.
.toISOString(): Returns an ISO8601 string that has been normalized to UTC. Will have a "Z" timezone indicator. See the native Date's specs for toISOString.
.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") or "Z"
zz	timezone offset hour, 2-digits (like "-07") or "Z"
zzz	timezone offset hour, 2-digits, and minutes (like "-07:00") or "Z"
w	ISO week number
ww	ISO week number, 2 digits
S	day-of-week ordinal (like "st", "nd", "rd")
i	ISO8601 format, without a timezone indicator
u	ISO8601 format, with a timezone indicator

Example:

vard=newXDate(2012,5,8);d.toString("MMM d, yyyy");// "Jun 8, 2012"d.toString("i");// "2012-06-08T00:00:00"d.toString("u");// "2012-06-08T00:00:00-07:00"

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

vard=newXDate(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:

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

Advanced:

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)
.setUTCWeek(week, year)
.setUTCDate(date)
.setUTCHours(hours)
.setUTCMinutes(minutes)
.setUTCSeconds(seconds)
.setUTCMilliseconds(milliseconds)

UTC Mode

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 computer's timezone and make a UTC date, a date without a timezone. A date in UTC-mode will have all of its "get" methods identical to its "getUTC" methods and won't experience any daylight-savings time.

A true argument can be appended to any of the constructors to make an XDate in UTC-mode:

d=newXDate(true);// the current date, in UTC-moded.toString();// "Mon, 24 Oct 2011 08:42:08 GMT"d=newXDate(2012,5,8,true);// values will be interpreted as UTCd.toString();// "Fri, 08 Jun 2012 00:00:00 GMT"d=newXDate('2012-06-08',true);// ambiguous timezone, so will be parsed as UTCd.toString();// "Fri, 08 Jun 2012 00:00:00 GMT"

Here are methods that relate to UTC-mode:

.getUTCMode(): Returns true if the date is in UTC-mode and false otherwise
.setUTCMode(utcMode, doCoercion): utcMode must be either true or false. If the optional doCoercion parameters is set to true, the underlying millisecond time of the date will be coerced in such a way that methods like getDate and getHours will have the same values before and after the conversion.
.getTimezoneOffset(): Returns the number of minutes from UTC, just like the native Date's getTimezoneOffset. However, if the XDate is in UTC-mode, 0 will be returned.

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

Utilities

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

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. You'll probably want to use new XDate() instead.
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=newXDate();d2=d1.clone().setUTCMode(true).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&n