chronoshift

Chronoshift

Chronoshift is a library to manipulate time with timezones

Installation

In node simply run: npm install chronoshift

In the browser you should use the browserified package/chronoshift.js

Initialization

Chronoshift uses WallTime.js under the hood and it needs to be initialized with timezone data before it can be used.

// Example timezone data can be found in lib/walltime/walltime-data.js
// it should be imported with require or AJAX
var tzData = require("./lib/walltime/walltime-data.js");

// Chronoshift's WallTime instance can be accessed like so:
chronoshift.WallTime.init(tzData.rules, tzData.zones);

Usage

Chronoshift can be used in two ways:

1. By using the provided floor, ceil, and move methods

Use chronoshift[period][fn](date, timezone, moveAmount) where

• period is one of ['year', 'month', 'day', 'hour', 'minute', 'second', 'millisecond']
• fn is one of ['floor, ceil, move']

var tz = Timezone.fromJS("America/Los_Angeles");

var hourStart = chronoshift.hour.floor(new Date("2012-11-04T00:30:00-07:00"), tz));

hourStart.getTime() === new Date("2012-11-04T00:00:00-07:00").getTime()

2. By using the Duration class

Construct a new duration with a ISO Duration string. Then you can call floor, ceil and move on it.

Note that floor and ceil only work for 'simple' durations like "P1x" and "PT1x".

var Duration = chronoshift.Duration;
var tz = Timezone.fromJS("America/Los_Angeles");

p1w = Duration.formJS('P1W');

var weekStart;

weekStart = p1w.floor(new Date("2013-09-29T01:02:03.456-07:00"), tz)
weekStart.getTime() === new Date("2013-09-29T00:00:00.000-07:00").getTime()

weekStart = p1w.floor(new Date("2013-10-03T01:02:03.456-07:00"), tz)
weekStart.getTime() === new Date("2013-09-29T00:00:00.000-07:00").getTime()

A duration can also be constructed from two dates and a timezone:

new Duration(
  new Date("2012-10-29T00:00:00-07:00")
  new Date("2012-11-05T00:00:00-08:00")
  tz
).toString() // => 'P7D'

new Duration(
  new Date("2012-01-01T00:00:00-08:00")
  new Date("2013-03-04T04:05:06-08:00")
  tz
).toString() // => 'P1Y2M3DT4H5M6S'

Useful!

Development

Clone the repository :

$ git clone https://github.com/implyio/chronoshift.git

Install the dependencies :

$ npm install

Watch :

$ gulp watch