Relay: [Modern] relay-compiler barfs at the word "subscription"

[mattkrick]

Using the todo-modern example app to reproduce (with a subscription set up on the server identical to the query):

query={graphql`
      subscription appQuery {
        viewer {
          ...TodoApp_viewer
        }
      }
    `}

results in:

Writing default
Error: Expected null to be a GraphQL composite type.

When I try it out on graphiql, it returns just fine.
I'd love to see a more helpful error (and support for the word subscription 😄 )

[josephsavona]

Thanks for reporting. It looks like the compiler is assuming that a type exists in your schema but the value is null. What does the root of your schema look like? Does it define a Subscription type? Note that subscription <name> ... is semantically different than query <name> ..., and that these correspond to different root types in the schema. Also note that QueryRenderer (which it appears you're using) accepts queries, not subscriptions. Take a look at RelayModernEnvironment for executing a subscription.

[mattkrick]

To reproduce, I modified the schema as follows (in todo-modern):

const Subscription = new GraphQLObjectType({
  name: 'Subscription',
  fields: {
    viewer: {
      type: GraphQLUser,
      resolve: () => getViewer(),
    },
    node: nodeField,
  },
});

export const schema = new GraphQLSchema({
  query: Query,
  mutation: Mutation,
  subscription: Subscription
});

After playing around with the 2nd param of Network.create, sendSubscription, requestSubscription I figured I was probably doing subs wrong, but I figured a better error in that spot might be good for when i inevitably make a typo in the root query & wonder which root query caused it.

[LeeWong]

@josephsavona Is there any document for how to get subscription working besides following the todo-modern example? Thanks.

[jamesone]

@mattkrick Hey! Did you end up successfully getting the subscription to work? If so how? Could you maybe post the code to your query renderer?

[mattkrick]

yeah, but it it ain't pretty :see_no_evil: with the goal of not releasing antipatterns into the wild, i'll keep it private for now, hopefully the relay folks give us an example or some docs soon :grinning:

[jamesone]

Ah okay! I'll be keeping an eye out for these docs 👀 In the meantime I'm not too sure what todo with the subscriptions 🤔

[wincent]

Docs: https://github.com/facebook/relay/commit/752856f8166fecb9399d8f02f078aef14592f532

[mattkrick]

oh that's _good_. i can see it now: updater + CmRDT payload + Draft.js = google docs

[mattkrick]

closing to keep issues clean