Is there a good way to have the client emit a

sealed class

for the response? I’d like to emit various states such as

loading

,

failure

, and

success

but I don’t want to have to implement this on every call, I’d rather just do it in one spot 😄

The main thing to be aware of is that in GraphQL, it is possible to have partial responses. So it's possible to have both errors and data

ahhh, ok, thanks! I’m thinking something like this? What do you think?

sealed class Response<out T> {
    object Loading : Response<Nothing>()
    data class Failure(
        val message: String,
        val errors: List<Error>? = null,
        val cause: Throwable? = null
    ) : Response<Nothing>()

    data class Complete<out T>(
        val value: T?,
        val errors: List<com.apollographql.apollo.api.Error>? = null
    ) : Response<T>()
}

fun <D : Operation.Data, T : Any, V : Operation.Variables> ApolloClient.stateful(
    query: Query<D, T, V>,
    retries: Long = 1,
    fetchType: ResponseFetcher = ApolloResponseFetchers.NETWORK_FIRST
): Flow<Response<T>> {
    return query(
        query
    )
        .toBuilder()
        .responseFetcher(fetchType)
        .build()
        .watcher()
        .toFlow()
        .retry(retries)
        .map {
            Response.Complete(it.data, it.errors)
        }
        .onStart {
            emit(Response.Loading)
        }
}

I’m having an issue with the

onStart

and

catch

since the I’m mapping to a

Complete

, it’s expecting that all types emitted to be

Complete

Any suggestions?

This looks promising. Is this not working?

i haven’t ran it yet 🙂