Simple GraphQL server

graphql-server.js

const express = require('express')
const graphqlHTTP = require('express-graphql')
const makeExecutableSchema = require('graphql-tools').makeExecutableSchema

const schema = makeExecutableSchema({
  typeDefs: `
    type Query {
      user: User
    }

    type User {
      id: ID!
      firstName: String
      lastName: String
      fullName: String
    }
  `,
  resolvers: {
    Query: {
      user: () => {
        // Replace this with the result of a database or network call...
        // Whatever we return here will be the first argument in any User field resolver.
        return Promise.resolve({ id: 1, firstName: 'John', lastName: 'Smith' })
      }
    },
    User: {
      fullName: (user) => `${user.firstName} ${user.lastName}`
      // The resolvers for the remaining fields just default to returning `user[fieldName]`.
    }
  }
})

const app = express()
app.use('/', graphqlHTTP({ schema, graphiql: true }))
app.listen(3000, () => console.log('Listening on: http://localhost:3000/'))