Hello, I’m trying to understand best practice for creating a CoroutineScope for some component I have. I don’t know what the difference is between these two approaches: CoroutineScope from Dispatcher:

class MyComponent {
  private val scope = CoroutineScope(<http://Dispatchers.IO|Dispatchers.IO>)
  
  fun close() {
    scope.cancel()
  }
}

CoroutineScope with Dispatcher + Job:

class MyComponent {
  private val job = Job()
  private val scope = CoroutineScope(<http://Dispatchers.IO|Dispatchers.IO> + job)

  fun close() {
    job.cancel()
  }
}

The second example is used e.g. in https://kenkyee.medium.com/android-kotlin-coroutine-best-practices-bc033fed62e7 I’m grateful for any insight! Thank you!

There is no difference. The

CoroutineScope

factory function will add a Job if one is not already in the

CoroutineContext

provided. The

CoroutineScope.cancel

method just calls

Job.cancel

. The only benefit to creating the

Job

explicitly first would be that you have easier access to it if you need it for other functionality besides

cancel

. You could still grab it yourself, though, or even add your own helper like:

fun CoroutineScope.join() = coroutineContext[Job]?.join() ?: error("Can not join CoroutineScope with no Job")

Thanks for responding! I appreciate the answer, that’s helpful