Expected<T, E> class

A type that contains either an expected value of type T or an error of type E.

Expected<T, E> is a powerful functional wrapper that mimics C++23's std::expected. It allows for robust error handling without relying on throwing exceptions.

Constructors

Expected.error(E error)
Creates an Expected containing an error.
const
Expected.value(T value)
Creates an Expected containing a successful value.
const

Properties

error → E
Returns the error value.
no setter
hashCode → int
The hash code for this object.
no setteroverride
hasValue → bool
Returns true if this object contains an expected value.
no setter
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
value → T
Returns the expected value.
no setter

Methods

map<U>(U mapper(T value)) → Expected<U, E>
Transforms the expected value of type T into a new value of type U using the provided mapper function.
mapError<F>(F mapper(E error)) → Expected<T, F>
Transforms the error value of type E into a new error of type F using the provided mapper function.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
override
valueOr(T defaultValue) → T
Returns the expected value if it exists, otherwise returns defaultValue.

Operators

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