Use Either with Future

Question

I want to use dartz functional style and do something like this:

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

But it seems that I can't do this:

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

So, how can I use Either with Future this way?

Solution

It's all about <generics>.

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

You got to give the compiler all the proper information:

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

// or

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

Comments

[Reiko Dev]

Helped a lot bro, ty