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scalafuturefor-comprehension

Converting a Future[Future[(String,String)]] to Future[(String,String)] in Scala using for comprehension

I've a Future[Future[(String,String)]] and I want to convert it into a Future[(String,String)] using a for comprehension.

Solution

  • Not necessarily with a for comprehension, a simple approach involves the use of flatMap over identity.

    Consider for instance

    import scala.concurrent.Future
import scala.concurrent.ExecutionContext.Implicits.global

def f: Future[Future[(String,String)]] = Future { Future {("a","aa")} }

    Then

    f.flatMap(identity)
res: scala.concurrent.Future[(String, String)] = Promise$DefaultPromise@1849937