Feature: #106681 - Support relative date formats in DateRange validator 

Description 

The DateRange validator of the form extension now supports relative as well as absolute dates in Y-m-d format.

This allows form integrators to define dynamic date constraints that are evaluated at runtime, such as ensuring a date of birth is at least 18 years in the past or that a date is in the future.

The following relative expressions are supported and follow the syntax of strtotime():

• Named dates: today, now, yesterday, tomorrow
• Relative offsets: -18 years, +1 month, -2 weeks, +30 days

These expressions can be used in the options.minimum and options.maximum properties of the DateRange validator.

Example 

Ensure that a date of birth is at least 18 years in the past:

type: Date
identifier: date-of-birth
label: 'Date of birth'
validators:
  -
    identifier: DateRange
    options:
      maximum: '-18 years'

Ensure that a date is in the future:

type: Date
identifier: event-date
label: 'Event date'
validators:
  -
    identifier: DateRange
    options:
      minimum: '+1 day'

Mixed absolute and relative dates are also supported:

validators:
  -
    identifier: DateRange
    options:
      minimum: '2020-01-01'
      maximum: 'today'

The form editor in the TYPO3 backend has been updated to accept these relative expressions in the date range fields. The HTML min and max attributes on the rendered <input type="date"> element are automatically resolved to absolute Y-m-d dates at render time.

Impact 

Form integrators can now use relative date expressions in the DateRange validator configuration. Existing form definitions using absolute dates will continue to work without changes.