This plugin provides time intervals for Moment.js. It also adds support for ISO 8601 duration expressions.

A time interval is defined by a start time, an end time, and a period representing the amount of time between start and end.

When creating a time interval you can specify the time window in absolute terms, like start and end time, or using a combination of absolute and relative values, like start and period, or period and end.

So, for example, you could create a time interval between April 2013 and May 2013. The period here would be of 1 month. Or you could create a time interval starting at May 1st, 2013 and ending a week later. The end date would be May 8th, 2013.

moment-interval adds methods to the moment object, as well as Moment and Duration instances, to let you do this along some other common time handling tasks.

Creates an Interval instance by specifying a string in the form of ISO 8601 time interval expression:

start-date or period/end-date or period

If you leave a blank date at one of the sides, the current date will be used. You can't have both sides of the interval neither as blank or period.

// using dates in both ends
var fromMarchToApril = moment.interval('2013-03-01/2013-04-01');

// using a start date and a period
var oneYearSinceApril2012 = moment.interval('2012-03-01/P1Y');

// using a period and an end date
var twentyEightDaysLater = moment.interval('/P28D')

// using a period and the current date
var oneHundredTwentySevenHoursBefore = moment.interval('P127H/')

// invalid usage
var voidTime = moment.interval('/');                // invalid!
var relativitySucks = moment.interval('P1D/PT8H');  // invalid!

Creates an Interval instance starting at Moment and ending at Moment+Duration.

// March 1st, 2013 to March 2nd, 2013
moment.interval(moment('2013-03-01'), moment.duration(1, 'day'));

Returns an Interval instance starting at Moment-Duration and ending at Moment.

// December 24th, 16:00 to December 25th, 00:00
moment.interval(moment.duration(8, 'hours'), moment('2013-12-25'));

Returns an Interval instance starting at Moment and ending at Moment.

// December 21st, 2012 to March 3rd, 2013
moment.interval(moment('2012-12-21'), moment('2013-03-21'));    

Similar to moment.interval(String) but uses the current Moment instance as one end of the interval, so you just need to specify the other end.

// Now to Tomorrow same time
moment().interval('/P1D');

Similar to moment.interval(Moment, Moment) but the current Moment instance is used as one end of the interval.

// January 2010 to June 2015
moment('2010-01').interval('2015-06');

Similar to moment.interval(Moment, Duration) or moment.interval(Duration, Moment) but the current Moment instance is used as one end of the interval.

// Sunday to Monday
moment().startOf('week').interval(moment.duration(-1, 'day'));

// Monday to Tuesday
moment().startOf('week').interval(moment.duration(1, 'day'));

Creates an Interval instance starting at Moment and ending at Moment+current Duration.

// July 9th, 2011 to July 10th, 2011
moment.duration(1, 'day').since(moment('2011-07-09'));

Creates an Interval instance starting at Moment+current Duration and ending at Moment.

// July 9th, 2011 to July 10th, 2011
moment.duration(1, 'day').until(moment('2011-07-10'));

moment-interval uses overloaded getters and setters in the same way Moment.js does. Calling these methods without parameters acts as a getter, and calling them with a parameter acts as a setter.

Sets or returns a Moment object representing the start time of the interval.

By default, setting a new start time will stretch or shrink the period and the end time will remain intact.

var selection = moment.interval('2010-06-01/2010-06-08');
selection.start();              // Moment object set at 2010-06-01
selection.period().humanize();  // "7 days" 

selection.start('2010-06-05');
selection.period().humanize();  // "3 days" 

To enforce the period and automatically adjust the end time according to the new start value, add the second argument keepPeriod as true.

selection.start('2010-06-01', true);
selection.end();                // Moment object set at 2010-06-04

Same as above, but with the end time.

Sets or returns a Duration object representing the period of the interval. Setting a new period will shrink or stretch the interval keeping the start time intact.

// a week from today
var selection = moment.interval('/P1W');
selection.end();    // Moment object set as (today + 1 week)

selection.period(moment.duration(2, 'weeks'));
selection.end();    // Moment object set as (today + 2 weeks)

Moves the interval backwards in time. You can either specify a period by passing a Duration object, or leave it blank and the interval will move backward by the current period.

var selection = moment.interval('P1W/2013-05-01');

// previous week
selection.backward();   // 2013-04-17/2013-04-24

// previous week
selection.backward();   // 2013-04-10/2013-04-17

// previous year
selection.backward(moment.duration(1, 'year')); // 2012-04-10/2012-04-17

Same as above, but moves the interval forward in time.

// next month
selection.forward(moment.duration(1, 'month'))

Same as above but the Duration argument is mandatory. This is a generic method for moving backward or forward depending on the duration (if it is negative or positive).

// previous week
selection.travel(moment.duration(-1, 'week'));

// next week
selection.travel(moment.duration(1, 'week'));

Checks the specified object and returns true if it's a valid Interval instance, or false otherwise.

moment-interval extends Durations by adding ISO 8601 duration expressions support:

PnYnMnDTnHnMnSnZ or PnW

While nZ is not part of the ISO standard, it has been implemented here as a way to specify milliseconds and is completely optional.

moment.duration('P1W');         // a week
moment.duration('P1DT2H30M');   // a day and 2 and half hours
moment.duration('PT500Z');      // half a second

Returns an ISO 8601 representation of the current Duration instance.

moment.duration(3, 'weeks').toISOString(); // "P3W"
moment.duration({days: 9, hours: 18}).toISOString(); // "P9DT18H"

moment-interval is freely distributable under the terms of the MIT license.