iso_date

Checks that the value is an ISO 8601 date without time, for example "2014-08-14".

Error codes: WRONG_DATE, FORMAT_ERROR

Live example · edit rules or inputOpen in playground

rules

{
    birth_date: 'iso_date'
}

{ birth_date: 'iso_date' }

input

{
    birth_date: '2014-02-30'
}

{ birth_date: '2014-02-30' }

Invaliderrors

{
  "birth_date": "WRONG_DATE"
}

Options form LIVR 2.5

LIVR 2.5

This form was added in LIVR 2.5. Implementations of LIVR 2.0 do not support it.

The 2.0 forms 'iso_date' and { iso_date: [] } do not change: they accept only YYYY-MM-DD, a valid date in the proleptic Gregorian calendar (1582-10-10 is valid, 1500-02-29 is not), and do not change the value. { iso_date: null } is the plain iso_date too.

The first argument, if there is one, must be an options object. { iso_date: 'x' }, { iso_date: 'today' } and { iso_date: ['x', { min: 'today' }] } are schema errors: LIVR 2.0 ignored them, so they never checked what they say. Don't pass arguments after the object: what happens to them depends on the implementation.

LIVR 2.5 adds an options object with bounds:

{ birth_date: { iso_date: { max: 'today' } } }
{ event_date: { iso_date: { min: 'yesterday', max: 'tomorrow' } } }
{ season:     { iso_date: { min: '2026-06-01', max: '2026-08-31' } } }

Option	Values	Default
min	a date bound	no bound
max	a date bound	no bound

Error codes: WRONG_DATE, DATE_TOO_EARLY, DATE_TOO_LATE, FORMAT_ERROR

• The value is YYYY-MM-DD, as in 2.0. The output is the value unchanged.
• A date bound is a date YYYY-MM-DD or one of 'today', 'yesterday' and 'tomorrow': the current date in UTC, one day before it, one day after it. 'current' from js-livr-extra-rules is a schema error.
• Dates are compared as calendar dates, and both bounds are inclusive. A date before min gives DATE_TOO_EARLY, after max gives DATE_TOO_LATE.
• { iso_date: {} } and { iso_date: [{}] } are the same as 'iso_date'. An unknown option or a wrong bound is a schema error.
• min later than max is a schema error when both are dates or both are relative ({ min: 'tomorrow', max: 'yesterday' }): no value could pass. A date and a relative bound are not checked, because the result depends on the day: { min: '2026-12-01', max: 'today' } accepts nothing before December, and that can be intended. With such bounds a value can be both before min and after max: min is checked first, so it gets DATE_TOO_EARLY.
• In every form, also in 'iso_date', a value that is not a string (a number, a boolean) gives WRONG_DATE (some 2.0 implementations gave FORMAT_ERROR for a boolean), and an object or a list gives FORMAT_ERROR. The format is checked before the bounds, so DATE_TOO_EARLY and DATE_TOO_LATE always mean a valid date.

For dates with a time, use iso_datetime. The format option of js-livr-extra-rules is not in 2.5: { iso_date: { format: 'datetime' } } is a schema error.

The current date

'today', 'yesterday' and 'tomorrow' depend on the current time of the system, always in UTC, never in the local time zone of the server. There is no API for it: tests fix the system clock with the usual tools of the language, as dev dependencies only, for example fake timers in JavaScript, Test::MockTime in Perl, php-mock in PHP, freezegun in Python or Timecop in Ruby. Where the language cannot replace the system clock (Rust, Go, Java, Swift, Dart without a runtime dependency), the implementation takes the time or a clock, for example as a validator option.