Medjool

A functional, mutation-free date and time transformation library. Heavily inspired by moment, but chooses composition over chaining.

Usage

.add(addend, date)

Adds addend number of milliseconds to the date you pass in and passes back a new Date object.

.subtract(subtrahend, date)

Subtracts subtrahend number of milliseconds from the date you pass in and passes back a new Date object.

.seconds(num) or .second(num)

.minutes(num) or .minute(num)

.hours(num) or .hour(num)

.days(num) or .day(num)

.weeks(num) or .week(num)

.months(num) or .month(num)

.years(num) or .year(num)

Converts num units into milliseconds. Warning: At the moment, month is implemented as 30 days, so it is best to skip that for now. There is an open issue in the issue tracker about what we want month to mean, semantically, but the most likely outcome will be to follow moment's lead here.

.format(mask, date)

This uses the excellent dateformat library, but the arguments are simplified and reordered and the function is curried. See dateformat documentation for help with mask strings. Also note that the utc and gmt arguments are gone, so use the UTC: or GMT: mask prefix.

.startOf(unit, date)

Returns a new date at the start of the unit string supplied. There are already curried helper functions available like: .startOfDay, .startOfWeek, etc. that have an arity of one.

.endOf(unit, date)

Returns a new date at the end of the unit string supplied. There are already curried helper functions available like: .endOfDay, .endOfWeek, etc. that have an arity of one.

This is really early on in the development, so it's far from ready for use. But, if you find it useful, feel free to hop in and contribute!

Contributing

The following areas need more work, and I welcome contributions:

• Month/quarters are not real units of time, and cannot be expressed in milliseconds. I'm thinking we need to allow for functions to be passed as the first argument in some of the helper functions so you have access to the Date object to do conditional checking. Seems like the only way to do things like addMonth(2).
• Documentation, including JSDoc and README. Love to get some help setting up the tooling around automatic documentation generation using JSDoc.
• Filing issues for 1.0 release: If there are useful things that momentjs provides that there is no issue filed for, please feel free to open an issue.