Underscore.date is a javascript date library that helps create, manipulate, and format dates without extending the Date prototype.
Author: Tim Wood
Version: 0.6.0
Note: There are some api changes that will break your code when upgrading from 0.4.1 to 0.5.0. Read about the changes in the changelog at the bottom of the page.
Install with npm
npm install underscore.date
Usage
var _date = require('underscore.date');
console.log(_date('September 9 1999').fromNow());
If underscore exists, underscore.date will mix itself into the underscore namespace, so you can use as you would use an underscore function.
_.date('September 9 1999').fromNow();
Otherwise, you should use _date.
_date('September 9 1999').fromNow();
The library works by creating a _date() wrapper object. To create that wrapper, you can pass any of the following data types in.
_date(1300291340510)
An integer value representing the number of milliseconds since 1 January 1970 00:00:00 UTC.
_date(new Date(2010, 1, 14, 15, 25, 50, 125))
Any valid Date object. For more information on Date objects, see the JavaScript Date documentation at MDN
_date([2010, 1, 14, 15, 25, 50, 125])
An array mirroring the parameters passed into Date.UTC().
[year, month = 0, date = 1, hours = 0, minutes = 0, seconds = 0, milliseconds = 0]
Any value past the year is optional, and will default to the lowest possible number.
_date()
If no value is passed to a 'dateInput' parameter, it will default to the current time using new Date().
_date() === _date(new Date())
_date("Dec 25, 1995")
A string that can be parsed by Date.parse().
_date("12-25-1995", "MM-DD-YYYY")
A string and a format string. The second string will be used as the format to parse the first string.
The format parts are similar to the formats from _date().format()
Important: Parsing a string with a format is by far the slowest method of creating a date. If you have the ability to change the input, it is much faster (~15x) to use Unix timestamps.
NOTE: The parser ignores non-alphanumeric characters, so both _date("12-25-1995", "MM-DD-YYYY") and
_date("12\25\1995", "MM-DD-YYYY") will return the same thing.
| Input | Output |
|---|---|
| M or MM | Month |
| D or DD | Day of month |
| DDD or DDDD | Day of year |
| YY | 2 digit year (if greater than 70, will return 1900's, else 2000's) |
| YYYY | 4 digit year |
| a or A | AM/PM |
| H, HH, h, or hh | 24 hour (for 12 hour time, use in conjunction with a or A) |
| m or mm | Minutes |
| s or ss | Seconds |
_date("12-25-1995", ["MM-DD-YYYY", "YYYY-MM-DD"])
A list of format strings to try to parse the input string.
This will find the format that is closest to the input formats. This is fundamentally problematic in cases like the following.
_date("05-06-1995", ["MM-DD-YYYY", "DD-MM-YYYY"]) // June 5th or May 6th?
Ideally, you should stick to one input format for creating dates.
Important: THIS IS SLOW. This should only be used as a last line of defense. Check out the comparisons at http://jsperf.com/underscore-date/2 if you don't believe me. It's the one on the bar graph that you can't even see, that's how slow it is.
underscore.date contains a number of utility functions for manipulating and formatting dates.
_date.add(object)
Adds time per the object passed in.
The object should have key value pairs as shown below.
{
ms : 200, // milliseconds
s : 10, // seconds
m : 10, // minutes (note: lowercase)
h : 2, // hours
d : 3, // days
M : 2, // months (note: uppercase)
y : 3 // years
}
All the parameters are optional. Also, there are no upper limits for the values, so you can overload any of the parameters.
{ ms : 1000000 } // a million milliseconds
{ d : 360 } // 360 days
If the day of the month on the original date is greater than the number of days in the final month, the day of the month will change to the last day in the final month.
Example:
_date([2010, 0, 31]) // January 31
_date([2010, 0, 31]).add({M : 1}) // February 28
_date.subtract(object)
Functions the same as _date.add(), only using subtraction instead of addition.
Example:
_date([2010, 1, 28]) // February 28
_date([2010, 1, 28]).subtract({M:1}) // January 28
_date.format(string)
Returns a human readable string based on the format string that was passed in.
var dateToFormat = new Date(2010, 1, 14, 15, 25, 50, 125);
_date(dateToFormat).format("dddd, MMMM Do YYYY, h:mm:ss a"); // "Sunday, February 14th 2010, 3:25:50 pm"
_date(dateToFormat).format("ddd, hA"); // "Sun, 3PM"
The formats are created by creating a string of replacable characters.
| Input | Output |
|---|---|
| Month | |
| M | 1 2 ... 11 12 |
| Mo | 1st 2nd ... 11th 12th |
| MM | 01 02 ... 11 12 |
| MMM | Jan Feb ... Nov Dec |
| MMMM | January February ... November December |
| Day of Month | |
| D | 1 2 ... 30 30 |
| Do | 1st 2nd ... 30th 31st |
| DD | 01 02 ... 30 31 |
| Day of Year | |
| DDD | 1 2 ... 364 365 |
| DDDo | 1st 2nd ... 364th 365th |
| DDDD | 001 002 ... 364 365 |
| Day of Week | |
| d | 0 1 ... 5 6 |
| do | 0th 1st ... 5th 6th |
| ddd | Sun Mon ... Fri Sat |
| dddd | Sunday Monday ... Friday Saturday |
| Week of Year | |
| w | 1 2 ... 52 53 |
| wo | 1st 2nd ... 52nd 53rd |
| ww | 01 02 ... 52 53 |
| Year | |
| YY | 70 71 ... 29 30 |
| YYYY | 1970 1971 ... 2029 2030 |
| AM/PM | |
| A | AM PM |
| a | am pm |
| Hour | |
| H | 0 1 ... 22 23 |
| HH | 00 01 ... 22 23 |
| h | 1 2 ... 11 12 |
| hh | 01 02 ... 11 12 |
| Minute | |
| m | 0 1 ... 58 59 |
| mm | 00 01 ... 58 59 |
| Second | |
| s | 0 1 ... 58 59 |
| ss | 00 01 ... 58 59 |
| Timezone | |
| z | EST CST ... MST PST |
| zz |
Eastern Standard Time ... Pacific Standard Time NOTE: Internet Explorer uses a different implementation of Date.toString(), so we are unable to retrieve the full string of the timezone, and will fall back to 'z'. So: Firefox, Chrome, Safari, etc. == 'Eastern Standard Time' Internet Explorer, etc. == 'EST' |
_date.from(date, withoutSuffix:boolean, asMilliseconds:boolean)
Returns a string as relative time ('minutes ago', '5 months ago', etc).
You can pass anything that you would pass to _date() as the first parameter, or a _date() object.
_date([2007, 0, 29]).from(_date([2007, 0, 28])) // "a day ago"
You can pass true as the second parameter to return without the prefixes and suffixes.
_date([2007, 0, 29]).from(_date([2007, 0, 28]), true) // "a day"
You can pass true as the third parameter to return as milliseconds.
The number of milliseconds returned will be positive if the date passed
in is later than the first date, and negative if the date passed in is earlier.
_date([2007, 0, 29]).from(_date([2007, 0, 28]), true , true) // -86400000);
_date([2007, 0, 27]).from(_date([2007, 0, 28]), true , true) // 86400000);
The base strings for this function can be customized with _date.relativeTime.
The breakdown of which string is displayed when is outlined in the table below.
| Range | Key | Sample Output |
|---|---|---|
| 0 to 45 seconds | s | seconds ago |
| 45 to 90 seconds | m | a minute ago |
| 90 seconds to 45 minutes | mm | 2 minutes ago ... 45 minutes ago |
| 45 to 90 minutes | h | an hour ago |
| 90 minutes to 22 hours | hh | 2 hours ago ... 22 hours ago |
| 22 to 36 hours | d | a day ago |
| 36 hours to 25 days | dd | 2 days ago ... 25 days ago |
| 25 to 45 days | M | a month ago |
| 45 to 345 days | MM | 2 months ago ... 11 months ago |
| 345 to 547 days (1.5 years) | y | a year ago |
| 548 days+ | yy | 2 years ago ... 20 years ago |
_date.fromNow(withoutSuffix:boolean, asMilliseconds:boolean)
Retuns the time from now.
A shortcut for _date.from(_date(), withoutSuffix:boolean, asMilliseconds:boolean).
Returns true if the year is a leap year, false if it is not
Examples :
_date([2000]).isLeapYear() // true
_date([2001]).isLeapYear() // false
_date([2100]).isLeapYear() // false
Add or switch a language.
To add a language, pass in the language key and the language constants. _date will cache the language based on the key for reuse.
_date.lang('pt', {
months : ["Janeiro", "Fevereiro", "Março", "Abril", "Maio", "Junho", "Julho", "Agosto", "Setembro", "Outubro", "Novembro", "Dezembro"],
monthsShort : ["Jan", "Feb", "Mar", "Abr", "Mai", "Jun", "Jul", "Ago", "Set", "Out", "Nov", "Dez"],
weekdays : ["Domingo", "Segunda-feira", "Terça-feira", "Quarta-feira", "Quinta-feira", "Sexta-feira", "Sábado"],
weekdaysShort : ["Dom", "Seg", "Ter", "Qua", "Qui", "Sex", "Sáb"],
relativeTime : {
future: "em %s",
past: "%s atrás",
s: "segundos",
m: "um minuto",
mm: "%d minutos",
h: "uma hora",
hh: "%d horas",
d: "um dia",
dd: "%d dias",
M: "um mês",
MM: "%d meses",
y: "um ano",
yy: "%d anos"
},
ordinal : function (number) {
return 'º';
},
}
Once a language has been set, all _date.format and _date.from calls will use that language. To change to another language,
call _date.lang('otherlang', { months : [] ... }).
Once a language has been cached, you can simply call the key to retrieve it from the cache. This allows for easily switching between multiple languages.
_date.lang('pt');
_date(1316116057189).fromNow() // uma hora atrás
_date.lang('en');
_date(1316116057189).fromNow() // an hour ago
There are languages in the ./underderscore.date.lang/ folder. You can require() them or add them to your page in the browser.
var _date = require('underscore.date.js')
var testLang = require('underscore.date.lang/test.js');
_date.lang(testLang.key, testLang.data);
<script src="underderscore.date.lang/leet.js"></script>
NOTE: The language should be included after underscore.date, and will automatically switch to that language.
To switch back to english, just use _date.lang('en') as that language is provided by default.
If you want to customize the wording of _date.format() and _date.from(), but don't want to create an entire language object,
the strings are exposed through the _date object. You can modify these however you see fit. However, calls to _date.lang will overwrite them.
Examples :
_date.relativeTime.future = "%s from now";
_date.relativeTime.past = "%s in the past";
_date.relativeTime = {
future: "in %s",
past: "%s ago",
s: "seconds",
m: "a minute",
mm: "%d minutes",
h: "an hour",
hh: "%d hours",
d: "a day",
dd: "%d days",
M: "a month",
MM: "%d months",
y: "a year",
yy: "%d years"
};
The strings used in _date.from().
future and past are used as the suffixes/prefixes.
For all these values, a single character refers to the singular, and an double character refers to the plural.
_date.weekdays = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
An array of day names, starting with Sunday.
_date.weekdaysShort = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
An array of abbreviated day names, starting with Sunday.
_date.months = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];
An array of the names of the months, starting with January.
_date.monthsShort = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
An array of the abbreviated names of the months, starting with January.
_date.ordinal = function (number) {
var b = number % 10;
return (~~ (number % 100 / 10) === 1) ? 'th' :
(b === 1) ? 'st' :
(b === 2) ? 'nd' :
(b === 3) ? 'rd' : 'th';
};
A function that returns a string to be appended to the number passed in. More information on ordinal numbers
Underscore.date performance tests
The unit tests can also be run in node by running node test.js on the root folder.
Floor vs bitwiseor vs bitwisenor vs parseint
Switch/case vs object of functions lookup
The folks over at date.js.
Everyone who helped with php.js date.
Ryan McGeary for his work on the jQuery timeago plugin.
Underscore.date is freely distributable under the terms of the MIT license.
Added _date.lang() support. Added support for passing multiple formats to try to parse a date. _date("07-10-1986", ["MM-DD-YYYY", "YYYY-MM-DD"]); Made parse from string and single format 25% faster.
Buxfix for issue 8 and issue 9.
Buxfix for issue 5.
Dropped the redundant _date.date() in favor of _date().
Removed _date.now(), as it is a duplicate of _date() with no parameters.
Removed _date.isLeapYear(yearNuumber). Use _date([yearNumber]).isLeapYear() instead.
Exposed customization options through the _date.relativeTime, _date.weekdays, _date.weekdaysShort, _date.months, _date.monthsShort, and _date.ordinal variables instead of the _date.customize() function.
Added date input formats for input strings.
Added underscore.date to npm. Removed dependancies on underscore.
Added 'z' and 'zz' to _.date().format(). Cleaned up some redundant code to trim off some bytes.
Cleaned up the namespace. Moved all date manipulation and display functions to the _.date() object.
Switched to the Underscore methodology of not mucking with the native objects' prototypes. Made chaining possible.
Changed date names to be a more pseudo standardized 'dddd, MMMM Do YYYY, h:mm:ss a'.
Added Date.prototype functions add, subtract, isdst, and isleapyear.
Changed function names to be more concise. Changed date format from php date format to custom format.
Initial release