BeforeDateValidator class

A validator that checks if the value date is less than date.

The BeforeDateValidator can be used with FieldControllers holding values of type DateTime. It ensures that the value is less than date.

If the value is null, it is treated as valid by default.

Properties

• date: The date the value must be strictly less than.
• message: An optional custom error message to display when invalid.

Example

FieldController<DateTime> field = FieldController(
  key: 'date',
  validators: [BeforeDateValidator(DateTime(2025, 7, 12))],
);

// If field.value = DateTime(2025, 7, 13), validation fails.
// If field.value = DateTime(2025, 7, 12), validation fails.
// If field.value = DateTime(2025, 7, 11), validation passes.

See also

• FormyValidator, the base class for custom validators.
• ValidationResult, which describes the outcome of validation.
• FieldController, which holds the field value to be validated.