Option<T> class sealed

Optional value wrapper for Rust-style present-or-absent values.

Use None() when no value is present, and Some(value) when a value is present even if that value is null.

const nickname = Some<String?>(null);

final label = switch (nickname) {
  None<String?>() => 'missing',
  Some<String?>(:final value) => value ?? 'present null',
};
Implementers

Properties

hashCode → int
The hash code for this object.
no setterinherited
isNone → bool
Whether this option is None.
no setter
isSome → bool
Whether this option is Some.
no setter
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

andThen<R>(Option<R> next(T value)) → Option<R>
Chains another option-producing operation when a value is present.
map<R>(R mapper(T value)) → Option<R>
Maps a present value and leaves absent values unchanged.
match<R>({required R some(T value), required R none()}) → R
Pattern matches this option.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited
unwrapOr(T fallback) → T
Returns the present value, or fallback when this option is absent.
unwrapOrElse(T fallback()) → T
Returns the present value, or computes one when this option is absent.

Operators

operator ==(Object other) → bool
The equality operator.
inherited