Err<T, E> class

A type that represents the failure Result of something.

Pattern matching is recommended for interacting with Result types.

Result<int, String> foo = Err('panic!');

if (foo case Err(value: var err)) {
  print('Error value: $err');
}
Inheritance
Available extensions

Constructors

Err(E value)
const

Properties

e → E
no setter
error → E
no setter
hashCode int
The hash code for this object.
no setterinherited
runtimeType Type
A representation of the runtime type of the object.
no setterinherited
v → E
no setter
val → E
no setter
value → E
final

Methods

and<U>(Result<U, E> other) Result<U, E>
Returns a Result value as Err<U, E> if this Result is Err<T, E>, otherwise returns other.
inherited
andThen<U>(Result<U, E> fn(T)) Result<U, E>
Returns a Result value as Err<U, E> if this Result is Err<T, E>, otherwise calls fn with the held Ok value and returns the returned Result.
inherited
call() → T
Shortcut to call Result.unwrap().
inherited
err() Option<E>
Converts this Result<T, E> into an Option<E>, discarding the held value if this is Ok.
inherited
expect(String message) → T
Returns the held value of this Result if it is Ok. Throws a ResultError with the given message and held Err value if this Result is Err.
inherited
expectErr(String message) → E
Returns the held value of this Result if it is Err. Throws a ResultError with the given message and held Ok value if this Result is Ok.
inherited
inspect(void fn(T)) Result<T, E>
Calls the provided function with the contained value if this Result is Ok.
inherited
inspectErr(void fn(E)) Result<T, E>
Calls the provided function with the contained error value if this Result is Err.
inherited
isErr() bool
Returns whether or not this Result is Err.
inherited
isErrAnd(bool predicate(E)) bool
Returns whether or not this Result is Err and that the held error value matches the given predicate.
inherited
isOk() bool
Returns whether or not this Result is Ok.
inherited
isOkAnd(bool predicate(T)) bool
Returns whether or not this Result is Ok and that the held value matches the given predicate.
inherited
iter() Iterable<T>
Returns an Iterable of the held value.
inherited
map<U>(U mapFn(T)) Result<U, E>
Maps a Result<T, E> to a Result<U, E> using the given function with the held value.
inherited
mapErr<F>(F mapFn(E)) Result<T, F>
Maps a Result<T, E> to a Result<T, F> using the given function with the held value.
inherited
mapOr<U>(U orValue, U mapFn(T)) Result<U, E>
Maps a Result<T, E> to a Result<U, E> using the given function with the held value if the Result<T, E> is Ok. Otherwise returns the provided orValue as Ok(orValue).
inherited
mapOrElse<U>(U orFn(), U mapFn(T)) Result<U, E>
Maps a Result<T, E> to a Result<U, E> using the given mapFn function with the held value if the Result is Ok. Otherwise returns the result of orFn as Ok(orFn()).
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
ok() Option<T>
Converts this Result<T, E> into an Option<T>, discarding the held error value if this is Err.
inherited
or<F>(Result<T, F> other) Result<T, F>
Returns a Result value as Ok<T, F> if this Result is Ok<T, E>, otherwise returns other.
inherited
orElse<F>(Result<T, F> fn(E)) Result<T, F>
Returns a Result value as Ok<T, F> if this Result is Ok<T, E>, otherwise calls fn with the held Err value and returns the returned Result.
inherited
toString() String
A string representation of this object.
inherited
unwrap() → T
Returns the held value of this Result if it is Ok.
inherited
unwrapErr() → E
Returns the held value of this Result if it is Err.
inherited
unwrapOr(T orValue) → T
Returns the held value of this Result if it is Ok, or the given value if this Result is Err.
inherited
unwrapOrElse(T elseFn()) → T
Returns the held value of this Result if it is Ok, or returns the returned value from elseFn if this Result is Err.
inherited

Operators

operator ==(Object other) bool
Compare equality between two Result values.
inherited