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Mastering Kotlin Coroutines

Functions Similar to coroutineScope

Learn about more functions that behave like coroutineScope.

We'll cover the following...

supervisorScope

The supervisorScope function also behaves like coroutineScope—it creates a CoroutineScope that inherits from the outer scope and calls the specified suspend block. The difference is that it overrides the context’s Job with SupervisorJob, so it’s not canceled when a child raises an exception.

package kotlinx.coroutines.app
import kotlinx.coroutines.*

fun main() = runBlocking {
   println("Before")

   supervisorScope {
       launch {
           delay(1000)
           throw Error()
       }

       launch {
           delay(2000)
           println("Done")
       }
   }

   println("After")
}
Using supervisorScope

We mainly use supervisorScope in functions that start multiple independent tasks.

Kotlin 1.5
suspend fun notifyAnalytics(actions: List<UserAction>) = 
    supervisorScope {
      actions.forEach { action ->
        launch {
          notifyAnalytics(action)
        }
      } 
    }

Silencing its exception propagation to the parent is not enough if we use async. When we call await, and the async coroutine finishes with an exception, await will ...