cats-effect: How to transform `List[IO]` to `IO[List]`

Question

I created a list of IO[Unit] in order to retrieve data from a list of URL. But now how I convert it back to a single IO[Unit] ?

Answer 1

You can do this in the following way

val x: List[IO[Unit]] = ???

import cats.implicits._

val y: IO[List[Unit]] = x.sequence

val z: IO[Unit] = y.map(_ => ())