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Last active August 27, 2015 14:45
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Scala Either
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Either.md

Working with Either

There are two ways to work with Either in Scala.

If you want to update only one side use a projection and map

response.right.map(_.parseJson.convertTo[Seq[String]])

If you want to update both sides then use a fold

response.fold(l => Left(l), r => Right(r))

Use some kind of bifunctor

def bimap[A,B,C,D](e: Either[A,B], f: A => C, g: B => D): Either[C, D] =
    e.fold(l => Left(f(l)), r => Right(g(r)))
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