TaskEither<L, R> class

TaskEither<L, R> represents an asynchronous computation that either yields a value of type R or fails yielding an error of type L.

If you want to represent an asynchronous computation that never fails, see Task.

Inheritance

• Object
• HKT2<_TaskEitherHKT, L, R>
• TaskEither

Mixed-in types

• Functor2<_TaskEitherHKT, L, R>
• Applicative2<_TaskEitherHKT, L, R>
• Monad2<_TaskEitherHKT, L, R>
• Alt2<_TaskEitherHKT, L, R>

Constructors

TaskEither(Future<Either<L, R>> _run())

Build a TaskEither from a function returning a Future<Either<L, R>>.

const

TaskEither.Do(DoFunctionTaskEither<L, R> f)

Initialize a Do Notation chain.

factory

TaskEither.flatten(TaskEither<L, TaskEither<L, R>> taskEither)

Flat a TaskEither contained inside another TaskEither to be a single TaskEither.

factory

TaskEither.fromEither(Either<L, R> either)

Build a TaskEither that returns either.

factory

TaskEither.fromNullable(R? r, L onNull())

If r is null, then return the result of onNull in Left. Otherwise return Right(r).

factory

TaskEither.fromNullableAsync(R? r, Task<L> onNull)

If r is null, then return the result of onNull in Left. Otherwise return Right(r).

factory

TaskEither.fromOption(Option<R> option, L onNone())

Build a TaskEither from option.

factory

TaskEither.fromPredicate(R value, bool predicate(R a), L onFalse(R a))

When calling predicate with value returns true, then running TaskEither returns Right(value). Otherwise return onFalse.

factory

TaskEither.fromTask(Task<R> task)

Build a TaskEither from the result of running task.

factory

TaskEither.left(L left)

Build a TaskEither that returns a Left(left).

factory

TaskEither.leftTask(Task<L> task)

Build a TaskEither that returns a Left containing the result of running task.

factory

TaskEither.of(R r)

Build a TaskEither that returns a Right(r).

factory

TaskEither.right(R right)

Build a TaskEither that returns a Right(right).

factory

TaskEither.rightTask(Task<R> task)

Build a TaskEither that returns a Right containing the result of running task.

factory

TaskEither.tryCatch(Future<R> run(), L onError(Object error, StackTrace stackTrace))

Execute an async function (Future) and convert the result to Either:

factory

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

alt(covariant TaskEither<L, R> orElse()) → TaskEither<L, R>

When this TaskEither returns Right, then return the current TaskEither. Otherwise return the result of orElse.

override

andThen<C>(covariant TaskEither<L, C> then()) → TaskEither<L, C>

If running this TaskEither returns Right, then return the result of calling then. Otherwise return Left.

override

ap<C>(covariant TaskEither<L, C Function(R r)> a) → TaskEither<L, C>

Apply the function contained inside a to change the value on the Right from type R to a value of type C.

override

bimap<C, D>(C mLeft(L l), D mRight(R r)) → TaskEither<C, D>

Define two functions to change both the Left and Right value of the TaskEither.

bindEither<C>(Either<L, C> either) → TaskEither<L, C>

Chain an Either to TaskEither by converting it from sync to async.

call<C>(covariant TaskEither<L, C> chain) → TaskEither<L, C>

Chain multiple functions having the same left type L.

override

chainEither<C>(Either<L, C> f(R r)) → TaskEither<L, C>

Chain a function that takes the current value R inside this TaskEither and returns Either.

chainFirst<C>(covariant TaskEither<L, C> chain(R b)) → TaskEither<L, R>

Chain a request that returns another TaskEither, execute it, ignore the result, and return the same value as the current TaskEither.

override

delay(Duration duration) → TaskEither<L, R>

Creates a TaskEither that will complete after a time delay specified by a Duration.

filterOrElse(bool f(R r), L onFalse(R r)) → TaskEither<L, R>

If f applied on this TaskEither as Right returns true, then return this TaskEither. If it returns false, return the result of onFalse in a Left.

flatMap<C>(covariant TaskEither<L, C> f(R r)) → TaskEither<L, C>

Used to chain multiple functions that return a TaskEither.

override

getOrElse(R orElse(L l)) → Task<R>

Convert this TaskEither to a Task.

map<C>(C f(R r)) → TaskEither<L, C>

If running this TaskEither returns Right, then change its value from type R to type C using function f.

override

map2<C, D>(covariant TaskEither<L, C> m1, D f(R b, C c)) → TaskEither<L, D>

Change the return type of this TaskEither based on its value of type R and the value of type C of another TaskEither.

override

map3<C, D, E>(covariant TaskEither<L, C> m1, covariant TaskEither<L, D> m2, E f(R b, C c, D d)) → TaskEither<L, E>

Change the return type of this TaskEither based on its value of type R, the value of type C of a second TaskEither, and the value of type D of a third TaskEither.

override

mapLeft<C>(C f(L l)) → TaskEither<C, R>

Change the value in the Left of TaskEither.

match<A>(A onLeft(L l), A onRight(R r)) → Task<A>

Pattern matching to convert a TaskEither to a Task.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

orElse<TL>(TaskEither<TL, R> orElse(L l)) → TaskEither<TL, R>

When this TaskEither returns a Left then return the result of orElse. Otherwise return this TaskEither.

pure<C>(C a) → TaskEither<L, C>

Returns a TaskEither that returns a Right(a).

override

run() → Future<Either<L, R>>

Run the task and return a Future<Either<L, R>>.

swap() → TaskEither<R, L>

Change this TaskEither from TaskEither<L, R> to TaskEither<R, L>.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

sequenceList<E, A>(List<TaskEither<E, A>> list) → TaskEither<E, List<A>>

Convert a List<TaskEither<E, A>> to a single TaskEither<E, List<A>>.

sequenceListSeq<E, A>(List<TaskEither<E, A>> list) → TaskEither<E, List<A>>

Convert a List<TaskEither<E, A>> to a single TaskEither<E, List<A>>.

traverseList<E, A, B>(List<A> list, TaskEither<E, B> f(A a)) → TaskEither<E, List<B>>

Map each element in the list to a TaskEither using the function f, and collect the result in an TaskEither<E, List<B>>.

traverseListSeq<E, A, B>(List<A> list, TaskEither<E, B> f(A a)) → TaskEither<E, List<B>>

Map each element in the list to a TaskEither using the function f, and collect the result in an TaskEither<E, List<B>>.

traverseListWithIndex<E, A, B>(List<A> list, TaskEither<E, B> f(A a, int i)) → TaskEither<E, List<B>>

Map each element in the list to a TaskEither using the function f, and collect the result in an TaskEither<E, List<B>>.

traverseListWithIndexSeq<E, A, B>(List<A> list, TaskEither<E, B> f(A a, int i)) → TaskEither<E, List<B>>

Map each element in the list to a TaskEither using the function f, and collect the result in an TaskEither<E, List<B>>.

tryCatchK<L, R, T>(Future<R> run(T a), L onError(Object error, StackTrace stackTrace)) → TaskEither<L, R> Function(T a)

Execute an async function (Future) and convert the result to Either: