elm-date-extra

Extra functions for working with Date values in Elm.

This package is organized into the following modules. Only examples of common uses are given below; see the docs for the full API.

Create

Create dates from parts.

import Date exposing (Month(..))
import Date.Create as Date

Date.fromParts 1999 Dec 31 23 59 0 0
-- <31 December 1999, 23:59, local time>

Create dates from strings in ISO 8601 format.

Date.fromIsoString "2000-01-01"
-- Just <1 January 2000, local time>

Date.fromIsoString "2009-W01-1T00Z"
-- Just <29 December 2008, UTC>

Date.fromIsoString "2016-218T20:00-03:00"
-- Just <5 August 2016, 23:00, UTC>

Date.fromIsoString "1/1/2001"
-- Nothing

Convert

Convert dates to formatted strings, using templates based on Date Format Patterns in [Unicode Technical Standard #35](http://www.unicode.org/reports/ tr35/tr35-43/tr35-dates.html#Date_Format_Patterns).

import Date exposing (Month(..))
import Date.Create as Date
import Date.Convert as Date

date = Date.fromParts 2007 Mar 15 13 45 56 67

Date.toFormattedString "EEEE, MMMM d, y 'at' h:mm a" date
-- "Thursday, March 15, 2007 at 1:45 PM"

Date.toUtcIsoString date
-- "2007-03-15T17:45:56.067Z"
-- (example has a local offset of UTC-04:00)

Math

Operate on the numeric properties of dates.

import Date exposing (Month(..))
import Date.Create as Date
import Date.Math as Date exposing (Interval(..))

date =
  Date.fromParts 1999 Dec 31 23 59 59 999

Date.floor Hour date
-- <31 December 1999, 23:00>

Date.ceiling Monday date
-- <3 January 2000, 00:00>

Date.add Week -2 date
-- <17 December 1999, 23:59:59.999>

Date.diff Day date (Date.add Week 2 date)
-- 14

{- List every Monday in the month of `date`. -}
Date.range Monday 1
  (Date.floor Month date)   -- <1 December 1999>
  (Date.ceiling Month date) -- <1 January 2000>
-- [<6 December 1999>, <13 December 1999>, <20 December 1999>, <27 December 1999>]

Extract

This module provides additional extractions to those available in the core Date library.

Facts

This module contains basic date information, like functions to convert between Date.Month values and month numbers as integers.