asynchronous - 将 Either 与 Future 一起使用

Question

我想使用 dartz 函数式风格并执行如下操作:

Either<Failure, Response> result = await remoteDataSource.request() // Future<Response> request();
    .then((response) => Right(response))
    .catchError((failure) => Left(failure));

但我似乎做不到:

error: A value of type 'Right< dynamic, Response>' can't be assigned to a variable of type 'Either< Failure, Response>'.

那么，我怎样才能以这种方式将 Either 与 Future 结合使用呢？

Answer 1

这都是关于<generics> .

.then((response) => Right(response)) // this is of type Right<dynamic,User>

您必须向编译器提供所有正确的信息:

.then((response) => Right<Failure, Response>(response))

// or

.then((response) => right(response)) // a helper function which returns an Either