GraphQL: Field Resolver Not Firing on Subscription Query? - graphql

Question

I've got a subscription query, MessageFolder_Subscription, that looks like this:
QUERY
const MESSAGEFOLDER_SUBSCRIPTION_QUERY = gql`
subscription ($localUserID: String!){
MessageFolder_Subscription(userID: $localUserID){
id
remoteUserData{
id
name_title
name_first
name_last
[...more fields...]
}
},
}
`;
Here's the schema for it:
SCHEMA
type myUserData {
id: String
gender: String
name_title: String
name_first: String
*[...more fields...]*
}
type messageFolder{
id: String
remoteUserData: myUserData
}
type Subscription {
MessageFolder_Subscription(userID: String!): messageFolder
}
Here's how I'm doing the resolvers:
RESOLVERS
const resolvers = {
//FIELD RESOLVER
MessageFolder_Subscription: {
subscribe: withFilter(
() => pubsub.asyncIterator(MSGFOLDER_ADDED_CHANNEL),
(payload, args) => {
debugger; <=== NEVER FIRES
if (typeof (payload) === 'undefined') {
return false;
}
let result = false;
const userId = Meteor.userId();
// let messageFolder = MessageFolder_Subscription.messageFolder;
result = (userId === args.fromID || args === MSGFOLDERargs.toID);
return result;
}
)
},
//ROOT RESOLVER
*[......more resolvers here.....]*
Subscription: {
MessageFolder_Subscription: {
subscribe: withFilter(
() => pubsub.asyncIterator(MSGFOLDER_ADDED_CHANNEL),
(payload, args) => {
debugger;
if (typeof (payload) === 'undefined') {
return false;
}
let result = false;
const userId = Meteor.userId();
// let messageFolder = MessageFolder_Subscription.messageFolder;
result = (userId === args.fromID || args === MSGFOLDERargs.toID);
return result;
}
)
}
}
When I mutate a related item, the MessageFolder_Subscription query is fired by pubsub as expected. Tracing through, I can see that it returns true.
But for some reason, the field resolver, for the field remoteUserData on MessageFolder_Subscription, never fires.
What am I missing?

Answer 1

Solved. I had to add the __typename: field:
const messageFolder_Subscription = {
__typename: 'messageFolder_Subscription',
id: userID,
}
...to the MessageFolder_Subscription subscription object, when it was created in the mutation resolver, prior to being passed to pubsub.