optional method

Formix<T, E> optional({
  1. bool isEmpty(
    1. T value
    )?,
})

Makes this validator optional - skips validation when empty.

By default, uses _defaultIsEmpty which checks for empty strings. Provide custom isEmpty predicate for other types.

final optionalEmail = emailRule.optional();
optionalEmail.validate(''); // Valid
optionalEmail.validate('test@example.com'); // Runs validation

Implementation

Formix<T, E> optional({bool Function(T value)? isEmpty}) =>
    Optional(validator: this, isEmpty: isEmpty ?? _defaultIsEmpty);