Date Uncertain field

A Drupal field type for dates as people actually record them: exact, partial ("March 1953", "1953"), approximate ("about 2005"), ranged ("between 1970 and 1976", "before 1990", "after 1978"), named ("the Grouping") or purely descriptive. Values are stored in GEDCOM date form including support for date phrases, with internally maintained values for earliest possible date, latest possible date and effective-value for sorting maintained for use by searching, faceting and sorting.

Post-Installation

Requires Drupal 11.2 or later (or 12) and PHP 8.3. Enable the module, then add an "Uncertain date" field to any fieldable entity type. Settings and named dates are under Configuration › Regional and language › Uncertain dates (`/admin/config/regional/date-uncertain`), and need the "Administer uncertain dates" permission.

Features

Use this date field when you are dealing with dates that are:

- specified as a range of possible values (from this to that)
- specified as being in a decade (the 1980s);
- specified by quarter of year or season (summer 1966);
- mixed values of ranges, calculated values and actual days.

... and you want to include them in sorting, searching (including facets) and similar actions.

Features include:

- support for locales: parse options enable the e.g. French version of "1980s" to be translated properly.
- defining words acceptable in input values, such as a point in time (Independence day) or a partial day (Christmas 1999).
- user input is retained, so can be reparsed as required;
- validation checks both in javascript and on submit;
- field formatters and widgets;
- optionally specify specific date for "sort as" with reasonable default calculated.

An extensive internal API is provided which includes the possibillity of replacing the base date parser and extending the module in several ways.

More information is available in the README file.

Submodules

A search_api helper module is included (not enabled by default). It tells search_api how to use the field properly and includes facets support.