Hi, any idea how to handle a `Flow` of `Either` ?...

# functional

[Sourabh Rawat]

Hi, any idea how to handle a Flow of Either ? I want to do a fold on it as a terminal operator.

[simon.vergauwen]

Do you want to short-circuit the Flow if you encounter Either.Left?

Otherwise you could write:

suspend fun <E, A> Flow<Either<E, A>>.fold(left: suspend (E) -> Unit, right: suspend (A) -> Unit) : Unit =
  collect { either ->
   either.fold({ left(it) }, { right(it) })
  }

[Sourabh Rawat]

I want to short-circuit.
Right now, I doing something like

either {
  lst.asFlow()
     .map { callServiceReturningEither(it) }
     .fold(initAcc) { acc, eitherRes -> acc.combine(eitherRes.bind()) } 
}

I am not sure if this will short circuit properly.

[simon.vergauwen]

This will short-circuit correctly 👍 Upon the first Either.Left.bind() inside fold it will short-circuit the `fold`/`Flow#collect` and it’ll return the encountered Either.Left.