Err<T extends Object, E extends Object> class

An Err<T, E> is a Result that represents a failure.

You can create an Err using either the Err(E) constructor or the Result.err(E) factory constructor.

Inheritance

• Object
• Result<T, E>
• Err

Available Extensions

• ResultOptionTransposer
• ResultResultFlattener

Constructors

Err(E err)

Create an Err result with the given error.

const

Properties

error → E

Wrapped error.

no setter

hashCode → int

The hash code for this object.

no setter, inherited

props → List<Object?>

The list of properties that will be used to determine whether two instances are equal.

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

stringify → bool

If set to true, the toString method will be overridden to output this instance's props.

no setter

Methods

and<U extends Object>(Result<U, E> res) → Result<U, E>

Returns res if the result is Ok, otherwise returns this.

override

andThen<U extends Object>(Result<U, E> op(T)) → Result<U, E>

Calls op with the Ok value if the result is Ok, otherwise returns this.

override

andThenAsync<U extends Object>(Future<Result<U, E>> op(T)) → Future<Result<U, E>>

Asynchronously calls op with the Ok value if the result is Ok, otherwise returns this.

override

err() → Option<E>

Converts the Result into an Option containing the error, if any. Otherwise returns None if the result is a value.

override

expect(String msg) → T

Unwraps a result, yielding the content of an Ok.

override

expectErr(String msg) → E

Unwraps a result, yielding the content of an Err.

override

fold<U extends Object, F extends Object>(U ok(T), F err(E)) → Result<U, F>

Invoke either the ok or the err function based on the result.

override

foldAsync<U extends Object, F extends Object>(Future<U> ok(T), Future<F> err(E)) → Future<Result<U, F>>

Asynchronously invoke either the ok or the err function based on the result.

override

isErr() → bool

Returns true if the option is a Err value.

override

isOk() → bool

Returns true if the option is a Ok value.

override

map<U extends Object>(U op(T)) → Result<U, E>

Maps a Result<T, E> to Result<U, E> by applying a function to a contained Ok value, leaving an Err value untouched.

override

mapAsync<U extends Object>(Future<U> op(T)) → Future<Result<U, E>>

Maps a Result<T, E> to Result<U, E> by applying an asynchronous function to a contained Ok value, leaving an Err value untouched.

override

mapErr<F extends Object>(F op(E)) → Result<T, F>

Maps a Result<T, E> to Result<T, F> by applying a function to a contained Err value, leaving an Ok value untouched.

override

mapErrAsync<F extends Object>(Future<F> op(E)) → Future<Result<T, F>>

Maps a Result<T, E> to Result<T, F> by applying a function to a contained Err value, leaving an Ok value untouched.

override

mapOr<U>(U op(T), U opt) → U

Applies a function to the contained value (if any), or returns the provided default (if not).

override

mapOrAsync<U>(Future<U> op(T), U opt) → Future<U>

Applies an asynchronous function to the contained value (if any), or returns the provided default (if not).

override

mapOrElse<U>(U op(T), U errOp(E)) → U

Maps a Result<T, E> to U by applying a function to a contained Ok value, or a fallback function to a contained Err value.

override

mapOrElseAsync<U>(Future<U> op(T), Future<U> errOp(E)) → Future<U>

Maps a Result<T, E> to U by applying a function to a contained Ok value, or a fallback function to a contained Err value.

override

match<R>(R okop(T), R errop(E)) → R

Invokes either the okop or the errop depending on the result.

override

matchAsync<R>(Future<R> okop(T), Future<R> errop(E)) → Future<R>

Asynchronously invokes either the okop or the errop depending on the result.

override

matchErr<R>(R errop(E)) → R?

Invokes the errop if the result is Err, otherwise does nothing.

override

matchOk<R>(R okop(T)) → R?

Invokes the okop if the result is Ok, otherwise does nothing.

override

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

ok() → Option<T>

Converts the Result into an Option containing the value, if any. Otherwise returns None if the result is an error.

override

or<F extends Object>(Result<T, F> res) → Result<T, F>

Returns res if the result is an Err, otherwise returns this.

override

orElse<F extends Object>(Result<T, F> op(E)) → Result<T, F>

Calls op with the Err value if the result is Err, otherwise returns this.

override

orElseAsync<F extends Object>(Future<Result<T, F>> op(E)) → Future<Result<T, F>>

Calls op with the Err value if the result is Err, otherwise returns this.

override

toString() → String

A string representation of this object.

inherited

unwrap() → T

Unwraps a result, yielding the content of an Ok.

override

unwrapErr() → E

Unwraps a result, yielding the content of an Err.

override

unwrapOr(T opt) → T

Unwraps a result, yielding the content of an Ok. Else, it returns opt.

override

unwrapOrElse(T op(E)) → T

Unwraps a result, yielding the content of an Ok. If the value is an Err then it calls op with its value.

override

unwrapOrElseAsync(Future<T> op(E)) → Future<T>

Unwraps a result, yielding the content of an Ok. If the value is an Err then it asynchronously calls op with its value.

override

unwrapOrNull() → T?

Unwraps a result, yielding the content of an Ok.

override

when<R>({required R ok(T), required R err(E)}) → R

Invokes either ok or err depending on the result.

override

whenAsync<R>({required Future<R> ok(T), required Future<R> err(E)}) → Future<R>

Asynchronously invokes either ok or err depending on the result.

override

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

unit<E extends Object>(E error) → Err<Unit, E>

Returns a new Err<Unit, E>