Kotlin Cooking Book

Coroutines.kt

import kotlinx.coroutines.flow.*
import kotlin.coroutines.CoroutineContext

/*
  Map each elements with a concurrency level
  Output elements can be shuffled
*/

suspend fun <T, R> Iterable<T>.mapConcurrently(
  level: Int,
  context: CoroutineContext? = null,
  block: suspend (T) -> R
): Iterable<R> {
  return asFlow().flatMapMerge(level) {
    flow { emit(block(it)) }.let {
      if (context != null) it.flowOn(context)
      else it
    }
  }.toList()
}