Datetime Extras
This module extends Drupal's core date and time functionality. It provides a widget that allows users to set an end date either by specifying an absolute date or a duration, and another widget for date-only selection lists.
What is the Datetime Extras module?
This aims to be a set of widgets, formatters, and other tools to extend the core Datetime and Datetime Range modules.
Features
"Date and time range with duration" (daterange_duration) widget
Allows content creators to select a start date/time and then optionally define the absolute end time (like the core widget) or to specify a duration (an offset relative to the start date/time). Requires duration_field module, version 8.x-2.0-rc3 or higher:
composer require 'drupal/duration_field:^2.0'
#2845081: Provide a datetime_range widget to define end time via a duration offset
"Select list, no time" (datetime_datelist_no_time) widget
Adds a date-only variant of core's "Select list" (datetime_datelist) widget.
#2823764: Add granularity options
Why do we need this module when Datetime is in core?
The Datetime module in core is really meant to provide a base set of time and date related features. But, it cannot provide everything that site builders need, nor will it ever. The Drupal 7 Date module (and friends) provide a rich set of features, and not all of these can (or should really) be supported by core. This module will provide a home for these needed features.
I have an idea? Will you implement it?
One of the goals of the Datetime Extras module is to try to avoid fragmentation of contrib modules for the Datetime space. So, if you have an idea, create an issue. Another goal, though, is to help mentor contributors to get core quality code into this module (that is why we are recruiting a lot of maintainers for the module). We may not be able to implement your idea right away, but we will be here to help you along the way. See the CONTRIBUTING.md file included with the project for additional information on how to contribute.
What is the relation between Datetime Extras and the Date module?
Datetime Extras is the logical progression of adding Datetime to core. Since the architecture of Drupal 8 (and hence Datetime) is radically different than Drupal 7, this module can mirror what core is doing. It also allows Drupal 7 to continue living without needing to worry about the Drupal 8 version. There will be no D8 port of the Date module. All effort is being focused on core and here in Datetime Extras.
Other D8 date-related projects of interest
date_recur: Support for recurring dates.
date_all_day: Support for "all-day" date ranges.