Optional<T> class

A validation rule that marks a field as optional.

If the value is not present (null, empty string, or empty list), the validation passes and skips all other rules. If the value is present, other rules will be validated against the value.

Inheritance

• Object
• ValidationRule<T>
• Optional

Constructors

Optional({String? message})

Creates a new instance of the Optional validation rule.

Properties

hashCode → int

The hash code for this object.

no setter, inherited

l10n → ValidatorLocalizations

The ValidatorLocalizations instance used for localization of validation messages. It's obtained through a service locator (sl) for convenience.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

message(String fieldName) → String

Retrieves the validation message to be displayed.

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

validate(T value, Map<String, FormFieldState> fields) → bool

Validates the given value against the validation rule.

override

validatorMessage(String fieldName) → String

Retrieves the validator message for the field.

override

Operators

operator ==(Object other) → bool

The equality operator.

inherited