index.js

import { ApolloServer } from '@apollo/server';
import { createServer } from 'http';
import { expressMiddleware } from '@apollo/server/express4';
import { ApolloServerPluginDrainHttpServer } from '@apollo/server/plugin/drainHttpServer';
import { makeExecutableSchema } from '@graphql-tools/schema';
import bodyParser from 'body-parser';
import express from 'express';

const port = 3000;

const typeDefs = `
    type Query {
        foo: String!
    }
    type Mutation {
        scheduleOperation(name: String!): String!
    }
`;

const resolvers = {
    Mutation: {
        scheduleOperation(_, { name }) {
            console.log(`Mocking operation: ${name}`);
            return `Operation: ${name} scheduled!`;
        }
    }, 
    Query: {
        foo() {
            return 'foo';
        }
    }
};

const schema = makeExecutableSchema({ typeDefs, resolvers });

const app = express();
const httpServer = createServer(app);

const apolloServer = new ApolloServer({
    schema,
    plugins: [
       // Proper shutdown for the HTTP server.
       ApolloServerPluginDrainHttpServer({ httpServer }),
    ]
});

await apolloServer.start();

app.use('/graphql', bodyParser.json(), expressMiddleware(apolloServer));

httpServer.listen(port, () => {
    console.log(`🚀 Query endpoint ready at http://localhost:${port}/graphql`);
    console.log(`🚀 Subscription endpoint ready at ws://localhost:${port}/graphql`);
});