How to use in GraphQL.js GraphQLSchema object way?

This is my client:

const client = createClient({
  url: 'wss://localhost:5000/graphql',
});

client.subscribe(
  {
    query: 'subscription { greeting }',
  },
  {
    next: (data) => {
      console.log('data', data);
    },
    error: (error) => {
      console.error('error', error);
    },
    complete: () => {
      console.log('no more greetings');
    },
  }
);

I succeed by GraphQL Schema Definition Language way just like the demo in readme (I only changed greetings to greeting). Got 101 Switching Protocols. And the client will print out the greeting five times in the browser console.

Server (Succeed version)

const schema = buildSchema(`
  type Subscription {
    greeting: String
  }
`);

// The roots provide resolvers for each GraphQL operation
const roots = {
  subscription: {
    greeting: async function* sayHiIn5Languages() {
      for (const hi of ['Hi', 'Bonjour', 'Hola', 'Ciao', 'Zdravo']) {
        yield { greeting: hi };
      }
    },
  },
};

createServer(
  {
    schema,
    execute,
    subscribe,
    roots,
  },
  {
    server,
    path: '/graphql',
  }
);

However, I failed on GraphQL.js GraphQLSchema object way. Got 101 Switching Protocols. But the client never prints out the greeting in the browser console.

Server (Failed version)

import { execute, subscribe, GraphQLObjectType, GraphQLSchema, GraphQLString } from 'graphql';
import { createServer } from 'graphql-transport-ws';

const GreetingGraphQLType = new GraphQLObjectType({
  name: 'Greeting',
  fields: {
    greeting: { type: GraphQLString },
  },
});

const subscription = new GraphQLObjectType({
  name: 'Subscription',
  fields: {
    greeting: {
      type: GreetingGraphQLType,
      resolve: async function* sayHiIn5Languages() {
        for (const hi of ['Hi', 'Bonjour', 'Hola', 'Ciao', 'Zdravo']) {
          yield { greeting: hi };
        }
      },
    },
  },
});

const schema = new GraphQLSchema({
  subscription,
});

createServer(
  {
    schema,
    execute,
    subscribe,
  },
  {
    server,
    path: '/graphql',
  }
);

Any idea? Thanks

[Hongbo-Miao]

Post full solution here to help future people save some time. Maybe we can add this to readme too : )

import { execute, subscribe, GraphQLObjectType, GraphQLSchema, GraphQLString } from 'graphql';
import { createServer } from 'graphql-transport-ws';
import { PubSub } from 'graphql-subscriptions';

const pubsub = new PubSub();

const subscription = new GraphQLObjectType({
  name: 'Subscription',
  fields: {
    greeting: {
      type: GraphQLString,
      resolve: (source) => {
        if (source instanceof Error) {
          throw source;
        }
        return source.greeting;
      },
      subscribe: () => {
        return pubsub.asyncIterator('greeting');
      },
    },
  },
});

const query = new GraphQLObjectType({
  name: 'Query',
  fields: {
    dummy: {
      type: GraphQLString,
      resolve: () => {
        return 'dummy';
      },
    },
  },
});

const schema = new GraphQLSchema({
  query,
  subscription,
});

setInterval(() => {
  pubsub.publish('greeting', {
    greeting: 'Bonjour',
  });
}, 1000);

createServer(
  {
    schema,
    execute,
    subscribe,
  },
  {
    server,
    path: '/graphql',
  }
);

[enisdenjo]

Aha, now I follow. I use the schema parsing for the sake of simplicity. I try to bring more focus on the lib itself, not the semantics of GraphQL. 😄