Tuesday, November 27th, 2007

Mad Cool Date Library

Category: Ajax, Announcements, JavaScript

Ok, I’ve seen some cool libraries in my time but I’ve just found one that is ssssooo cool that I didn’t want to wait to post about it until tomorrow (sorry Dion!).

So I get this email from a bud asking me to check out this date handling library and I’m figuring “great, Yet Another Date Library”. So I jump on over to Datejs.com to check it out and I’m presented with a nice looking site. I mean the little ninja dude at top is pretty slick! Anyways, I digress.

I start reading up on it and I see the usual pitch:

Datejs is an open-source JavaScript Date Library.

Comprehensive, yet simple, stealthy and fast. Datejs has passed all trials and is ready to strike. Datejs doesn’t just parse strings, it slices them cleanly in two.

Read that before, must be the same ole, blah, blah. So I look for like a date picker or something and all I see is a text box. Hmm. I see some suggestions listed below it:

So I give it a go and…woah!

Okay, lucky try. I know if I try that t+5years, it’s gonna choke.

Holy cow!!! All I have to say is wow. This is a VERY cool date library and definitely unique. I’ve not seen anything like this.

Datejs is the brainchild of Geoffrey McGill and the team at Coolite. It was developed to handle both parsing, formatting and processing of dates within the JS language. Apart from its incredible parsing capabilities, it also supports a TON of different language formats!

All 150+ CultureInfo files have been pre-compiled and are available within the same /build/ folder as date.js. Each culture file includes translations for many of the strings used in the Datejs library. Some strings have not been translated, although will be filled in over time as the community contributes.

The widget does a complete Date.parse(text) on each keystroke. Notice that no ‘date format’ is passed into the Parser. The Parser figures everything out on it’s own.

The API is also so simple to use. I mean just look below at the code examples. It doesn’t get much easier then that:

// What date is next thursday?

// Add 3 days to Today

// Is today Friday?

// Number fun

// 6 months from now
var n = 6;

// Set to 8:30 AM on the 15th day of the month
Date.today().set({ day: 15, hour: 8, mintue: 30 });

// Convert text into Date
Date.parse(‘t + 5 d’); // today + 5 days
Date.parse(‘next thursday’);
Date.parse(‘February 20th 1973′);
Date.parse(‘Thu, 1 July 2004 22:30:00′);

Overall, Datejs is REALLY impressive and I’m definitely going to see where I can use it in. Datejs is released under the MIT License and available for download at GoogleCode.

Posted by Rey Bango at 6:18 pm

4.1 rating from 84 votes


Comments feed TrackBack URI

Very cool! I need a server side version of this. Maybe it can be run using Rhino?

Comment by Jeff — November 27, 2007

I was hoping, “Christmas,” would work since it is coming up!

Comment by Jordan — November 27, 2007

rememberthemilk.com has always (as far as I know) had date parsing like this.

Thing is, some people don’t like the user interface on this because they shy away from the keyboard, thinking the mouse interaction with little calendars is better. Actually typing in a date can be much faster.

Comment by Andy — November 27, 2007

But what is definitely cool is the I18N support.

Comment by Andy — November 27, 2007

Hmmm. Looks like the same idea as Simon Willison’s date control that I’ve been using for forever (he announced in 2003 apparently: see http://simonwillison.net/2003/Oct/6/betterDateInput/).

Willison’s javascript library doesn’t have as many different formats (t +5) but it has the same basic idea of using free form date input plus a few special ones like “next friday”, etc… It’d be nice to see the idea spread – why force users to enter in a format like mm-dd-yy or click on a popup calendar?

Comment by metapundit — November 27, 2007

how about “first monday next month”? it seems to fail…

Comment by marius — November 27, 2007

Nice library, but a shame that it splooges methods and properties all over the Date and Number prototypes :(

Comment by Guy Fraser — November 27, 2007

Perl has had this (and it can be serverside.)

Its called Date::Manip.


Comment by Jeremiah — November 27, 2007

If you’re using php, strtotime does this also.

Comment by tuan — November 27, 2007

Anyone know something similar for python?

Comment by Braydon Fuller — November 27, 2007

Try put in “the day after tomorrow”.

Comment by Simon Jia — November 27, 2007


Comment by Michael — November 27, 2007

Very cool, but the more complex you make your “date” the more confused it gets… while I wouldn’t expect “tomorrow last april +5years” to be a common entry, it doesn’t currently work, and there are some common phrases that don’t parse will (like the above “day after tomorrow” phrase).

All in all though, I gave it 5/5, its a nifty tool and approaches user interaction in a different way. I’d use it in my stuff.

Comment by Jon Hartmann — November 27, 2007

The phrase “last april april 2008″ really throws it for a loop, heh.

Comment by Jon Hartmann — November 27, 2007

This isn’t a particularly novel way of parsing strings. While the first implementation I’ve seen in JS, as always the GNU people got ahead of us: this is just copying the GNU Date Input Standard:

PHP includes a function that does more or less the same, called strtotime:
which parses the given string into a Unix timestamp.

Comment by Pavel Panchekha — November 27, 2007

Oh gosh! The suggested examples actually work! Who would have thought?!?

Rey, are you kidding me?

Comment by Martin — November 27, 2007

@Martin: Dude, just go with the flow. I was trying to build it up to the climax. ;)

Comment by Rey Bango — November 27, 2007

Nice parsing!

Use clearDate() after Date.parse() if just want date and not date/time.

Would be cool if you could say: “Next christmas” or “Boxing day 2010″ (although not sure where can find good cross country db of holidays – and irregular dates like easter are hard!).

Comment by Morris — November 27, 2007

Meh, wake me up when “my birthday” works.


Comment by Matt — November 27, 2007

Is it just me? None of these common ones work:

day after tomorrow
8 days from now
4 days after tomorrow
thursday week
10 minutes from now
11:30 GMT

Comment by VLC — November 28, 2007

@VLC: I know the developer of the lib is watching it so offer up your suggestions or contact them directly via the site. I’m sure they’d be interested in hearing about it.

Comment by Rey Bango — November 28, 2007

Hey Rey, so why would Dion get mad that you released the news today? Seems counterintuitive. You guys broadcast news… seems as though you’d want to broadcast more and more news, and as soon as possible.

Comment by Olmo Maldonado — November 28, 2007

@VLC (and others) Thanks for noting all the edge cases! There all fantastic suggestions and we’ll feed these into future test cases.

A couple thoughts…

Please note/remember this is an Alpha-1 release. This is our first kick at the can and it’s only going to better from here. The goal of the Alpha-1 Parser was to provide support for pretty much 100% of the commonly understood/accepted date formats, support 150+ cultures and make it wicked-ass *fast*. That I think we achieved. Check out the test suite to see what’s currently supported by the parser (http://www.datejs.com/test/).

Now it’s onto the next stage… more relative date support, like all the suggestions above. We’ve also come up with a plan to make the Parser even faster. Things get weird when you start to hit terminal velocity on the browsers JavaScript engine, but we have a plan, and it will be cool.

Keep the parsing failures coming! I want to hear about them all and each is being diligently recorded.

Comment by Geoffrey McGill — November 28, 2007

Looks very similar to the date picker of RTM …. hey, still cool, nice pick, Rey.

Comment by Nikola — November 28, 2007

@Jon Hartmann

The phrase “last april april 2008″ really throws it for a loop, heh.

It looks like the parser is adding the “2008” to “last april (2007)” and coming up with a year of 4015. Very strange. But, should be an easy fix. Thanks for pointing out the problem.

Comment by Geoffrey McGill — November 28, 2007

@Nikola – Thanks for pointing out the date picker in RTM. I just signed up for an account. Theirs is a pretty similar concept, although a little limited in the amount of acceptable formats. I’m sure they would benefit immensely by ripping out their existing parsing and plugging in Datejs.

Comment by Geoffrey McGill — November 28, 2007

Nice library. I miss a little more documentation about how to change the input language, and the tests are quite impressive too; what test library are you using?

Comment by Ignacio Coloma — November 28, 2007

Nice work! todoist.com has this as well when you set reminders. It still needs more “magic words” but that’s just a matter of time. A Multilingual version would be the killer app. ;)

Comment by Alex — November 28, 2007

This is all very nice but it’s kinda academic when you consider that the two most common date formats used by real people are mm/dd/yyyy (in the US) and dd/mm/yyyy (in the rest of the world). For dates such as 11/12/2007, this class is worse than useless.

Comment by Tamlyn — November 28, 2007

@Tamlyn Oh my. *sigh* What does “real people” mean exactly? I appreciate your comments, but things are a little different in the “real world”.

Comment by Geoffrey McGill — November 28, 2007

Seems a bit flakey still

“tomorrow+1day” and “tomorrow” gives the same result.

Nice idea though… will be good if the issues are ironed out.

Comment by Rory — November 28, 2007

I like the random funny error messages. I just noticed one bug with “sat” or “saturday” it came up with Thursday November 1st.

Comment by Chris O'Brien — November 28, 2007

11/12/2007 is 11th of December, not November 12 for most of the world. (The states that use yyyy-mm-dd are fine of anyway.)

Only Canada, Micronesia, Palau, Philippines and the United States use the month/day format fully or partly.

This is a parsing problem without a good solution. But you could at least parse 11.12.2007 to 11th of December. In dot is never used as a separator in the mm/dd format.

Comment by Martin — November 28, 2007

@geoffrey Surely you agree that the *vast* majority of people, when faced with a free-form date input field, will enter a date as either dd/mm/yy(yy) or mm/dd/yy(yy) rather than any of the other forms that your library (very elegantly) supports? I just feel that the utility of such a library is very limited by the fact that these formats are ambiguous (not your fault, of course).

Comment by Tamlyn — November 28, 2007

Sweet, before I had to send the date through php’s strtotime function and back. I wonder how this compares to that and Remember the Milk ( which I use daily ).

– Troy

Comment by Troy — November 28, 2007

@Geoffrey–any particular reason the +format doesn’t work with anything over 99? +99days/months/years works, but +100 doesn’t.

Comment by Jack Viers — November 28, 2007

This is cool. I like the parser and the locale stuff, I haven’t seen much like it before.

My favourite is the neat extensions to the Date prototype.

(3).days().ago(); is awesome!

Comment by Daniel Skinner — November 28, 2007

Wonderful library.
Anyone of you clicked on the eyes of the ninja in the header?

Comment by puRe — November 28, 2007

@geoffrey apologies for my ill-informed comment, it was still a bit early in the morning for me and I hadn’t had my coffee! When I said “worse than useless” I was thinking of a scenario where a ‘classic’ date input field would be replaced with this free input field without specifying a format. In this situation it could easily be highly detrimental to usability. But in a web app context it makes a lot more sense once a user learns some of the input formats available (and where the app is aware of the user’s locale/’culture’).

As an open source developer myself I am aware of the frustration caused by people criticising your work without taking the time to understand it first so I really should have known better!

Comment by Tamlyn — November 28, 2007

@Geoffrey McGill
Thanks for the response… like I said, the phrase doesn’t really make sense, but it does throw it for a loop. Looks like specifying a month and a year together give it problems… “tomorrow, april 2008″ yields a date in the 41st century as well.

Comment by Jon Hartmann — November 28, 2007

Pretty innovative! Hope they keep it up.

Comment by Jay — November 28, 2007

for JSP see an appropriate taglib here http://www.servletsuite.com/servlets/dateaddtag.htm for example

Comment by Dmitry — November 28, 2007

Nice work, Geoffrey! I’m definitely going to keep an eye on this and I look forward to future releases.

Comment by Cal Jacobson — November 28, 2007

Very slick. Any chance of getting start and end dates based on an implied range?

ie “July 2008″ becomes:

{start: new Date(2008, 7, 1, 0, 0, 0, 0),
end: new Darte(2008, 8, 1, 0, 0, 0, 0)}

Comment by David — November 28, 2007


very nice lib, loved it. Question: Is there a way to convert one format to the other?
* a search in a webservice returns a date in mdy format, and we need to show in dmy format.
* the user types a date in dmy format, and we need to use this in the search on the webservice which uses mdy.


Comment by Fabio Lima — November 28, 2007

There’s a Ruby library called Chronic (http://chronic.rubyforge.org/) that handles this same sort of thing (though not client-side, obviously). Based on the comments here, it sounds like it might have a little wider coverage in terms of what it’ll handle.

Comment by John Price — November 28, 2007

Very impressive in thinking outside the box especially. Practical wise though – it’s the box that I and I think many appreciate and want. I want to see the big picture – I want to see the calendar. I want to see what day is the last of the month or what are the dates of each Saturday. I want something to pick from. I want to see the whole month or week. Anyway, it’s still a very cool tool.

Comment by Eric — November 28, 2007

Look at the PHP functions for date… they are just connecting that with AJAX… sure it’s nice to have, but it doesn’t deserve this type of hype… you asshat

Comment by you're an idiot — November 28, 2007

…wow trolls rule

Comment by Jon Hartmann — November 28, 2007

What about fortnights! Even with the En-GB / En-AU l10n files there are no fortnights. I guess it shows how difficult i18n can be — there are heaps of other locale-specific concepts like “再来週”(JA) for “the week after next”. And do Americans say “Friday week” too, meaning “Friday next week”?

It’s fun to pick apart other people’s code huh. Glad it’s not my date library under scrutiny.

Comment by skold — November 28, 2007

@Geoffrey McGill, idea about the dd/MM/YY and MM/dd/YY problem:

In many cases, it is hard to know what culture visitors are from. One way of solving this would be to have the library be able to automatically detect ambigous dates and create a popup where people could select what date they actually meant.

This could possibly be done directly, or at least there could be an API getting a suitable set of strings/suitable information for a popup. Choice could be remembered in a cookie or available so the library user could put it in persistent storage somewhere.

Comment by Eivind Eklund — November 29, 2007

Anything like this for Java?

Comment by okohll — November 30, 2007

@Eivind Eklund – The Datejs library does not include user interface components. It’s just code API. Any kind of popup message would have to be created by the developer. The library deals with ambiguous dates very elegantly, but the key is that the developer should detect the user-agent culture and serve up the appropriate culture-specific Datejs file. The library is completely oblivious of the user-agent. Just serve up the appropriate culture-specific file and there should be very few problems.
Another option would be to restrict user entry to only two possible formats (“dd/MM/yy” and “MM/dd/yy”), use .parseExact() instead of .parse() and then prompt the user each time to confirm which format/date they thought they were entering when either the month or day is 12 or lower. But that all seems rather goofy.

Comment by Geoffrey McGill — December 3, 2007

@okohll – We’re very interested in porting the library (especially the Parser) to other Languages. Work should start on ports to Ruby and C# very shortly. Porting to Java should be trivial after the C# version is complete (or vice-versa). Feel free to bring up the topic in the Datejs Forum if you’re interested in working on a Port.

Comment by Geoffrey McGill — December 3, 2007

Baaah…. It can’t even tell “My birthday” ;-)

It looks very nice, I’ll have it in mind the next time the need arise.

Comment by MichaelSchoeler — December 19, 2007

Nice library, but a shame that it splooges methods and properties all over the Date

Comment by koreanplywood — December 25, 2007

I think that hte mm/dd/yyyy problem isn’t as bad as you guys make it out to be. It might be a problem for those other parsing libraries, but you are overlooking the fact that you can reparse on EVERY KEYSTROKE and give instant feedback. When you type in a date, you know instantly what the library thinks you meant, and you can easily make corrections based on that feedback.

It might be a legitimate criticism if you had to *submit* with faith that the library undestood what you meant, wait 4 seconds for the next page to load, and find that you’ve accidentally booked for the wrong month. But this just won’t happen with instant feedback systems like this.

Comment by Breton — April 8, 2010

Leave a comment

You must be logged in to post a comment.