datetimejs

DatetimeJS

This is a shameless (or perhaps shameful) imitation of Python's datetime library for JavaScript. It provides methods for creating, comparing, formatting and parsing dates and times.

Motivation

This library existed a bit longer than it may seem from commit logs and other information. It has been sitting on my hard drive much longer than some of the other libraries out there that provide things like strftime formatting. Unfortunately, I have not released it until now because I was rather busy with other things. It just so happened that I had time on my hands, so I decided to polish and release this.

Another reason is that I have started to use MomentJS, and I hated it with passion. There are many reasons why strftime formatting is great, and habit is not even the first reason that comes to mind. Without going further into philosophical discussion, I consider strftime formatting to be superior and I want to use it in JavaScript. Period.

Installation

The datetime.js module is in UMD format, and it is usable in both the browsers and NodeJS. It has no external dependencies.

On Node, you can install using NPM:

npm install datetimejs

For browsers, you can simply add it using a <script> tag or require it as you normally do if you use RequireJS and similar AMD loaders.

It is also installable with volo:

volo add foxbunny/datetimejs

Basic usage

Since the juicy bit is strftime formatting, let's see an example of that first.

var dt = require('datetime');  // if you need to
var date = new Date(2014, 4, 12, 14, 0, 0);
dt.strftime(date, 'The year is %Y, around %i %p on %b %d');
// returns 'The year is 2014, around 2 p.m. on May 12'

Ideally, we would be able parse using the same formatting string and the result we've got from #strftime(), but that's just not possible right now. So we'll go easy with a slightly more reasonable example.

date = '9/2/2013 11:45 a.m.'
dt.strptime(date, '%n/%D/%Y %i:%M %p');
// Returns Date object for Mon Sep 02 2013 11:45:00

But formatting and parsing isn't all. How about finding out the difference in time between two Date objects?

// Wrapping it in immmediate-execution for people who are 
// trying this in a shell.
(function() {
    date = new Date();
    setTimeout(function() {
        var date1 = new Date();
        var delta = dt.datetime.delta(date, date1)
        console.log('Took me ' + delta.seconds + ' seconds');    
    }, 5400);
}());
// Will eventually print 'Took me 6 seconds'

Or maybe you don't need an exact delta. You only need to know if something is before or after?

var date = new Date(2013, 6, 12);
var date1 = new Date(2013, 6, 15);
dt.datetime.isAfter(date, date1); // false
dt.datetime.isBefore(date, date1); // true

Sorting dates is also quite easy:

dt.datetime.reorder(
    new Date(2013, 6, 12),
    new Date(2013, 4, 10),
    new Date(2013, 5, 15)
);
// returns [Date(2013, 4, 10), Date(2013, 5, 15), Date(2013, 6, 12)]

API documentation

Yes, on TODO list. Meanwhile, look at the CoffeeScript source in the src directory (no, really, just read the comments, even if you don't know any CoffeeScript).

Reporting bugs

Report all your issues (related to this library, of course) to the GitHub issue tracker.

Changelog

0.1.0

Apart from many bugfixes and additonal unit tests...

zeroPad API change

The zeroPad now takes one extra argument tail, which allows padding from the tail end of float numbers.