Reactive way of returning `Map<Long,T>` - spring-boot

Question

I am learning reactive. In an MVC project I have a service method (and the controller has the same signature) like this:
#Override
public Map<Long, Question> getQuestions() {
List<Question> questions = questionRepo.findAllByType(Type.A);
return questions.stream()
.collect(Collectors.toMap(q -> q.getId(), q -> q));
}
Resulting in something similar to this:
{
1: {id: 1, ...}
2: {id: 2, ...}
...
}
Now, switching to reactive and kotlin coroutines. What is the proper way to implement this in a reactive way?
This is the signature of the repository:
interface QuestionRepository : CoroutineCrudRepository<Question, Long> {
#Query("select * from Question q where type = :type")
fun findAllByType(type: Type): Flow<Question>
}
Approaches
From what I think so far using Mono<Map<Long,Question>> seems to make no sense as it would require to block for building the inner map.
Flow<Map<Long,Question>> Does not make sense either, because we do not populate multiple maps.
So my best approach for now is not using a Map...
override fun getQuestions(): Flow<Question> {
return questionRepo.findAllByType(Type.A)
}
...but this would require to change the frontend code (it now needs to convert the list to a map).
I also think of
override fun getQuestions(): Flow<Pair<Long?,Question>> {
return questionRepo.findAllByType(Type.A).map { it.id to it }
}
but this would require the frontend to change as well, because the output would look like
[{"first":1,"second":{"id":1, ...}]
Are there other, better approaches? How would you implement it?
UPDATE
added repository.

Answer 1

Assuming the Flow emits elements one at a time that you want to put into a single Map in the client code, then you can collect them into a MutableMap like this and return it.
suspend fun getQuestions(): Map<Long, Question> {
val map = mutableMapOf<Long, Question>()
questionRepo.findAllByType(Type.A)
.collect {
map[it.id] = it
}
return map
}
If your downstream client code is not expecting a suspend function, I guess you need to wrap this in runBlocking, and presumably the downstream code is already handling the fact that this is a long-running function call.
override fun getQuestions(): Map<Long, Question> = runBlocking {
val map = mutableMapOf<Long, Question>()
questionRepo.findAllByType(Type.A)
.collect {
map[it.id] = it
}
map
}