The express-graphql module provides a simple way to create an Express server that runs a GraphQL API.
import { graphqlHTTP } from "express-graphql" // ES6var { graphqlHTTP } = require("express-graphql") // CommonJS
graphqlHTTP({  schema: GraphQLSchema,  graphiql?: ?boolean,  rootValue?: ?any,  context?: ?any,  pretty?: ?boolean,  formatError?: ?Function,  validationRules?: ?Array<any>,}): Middleware
Constructs an Express application based on a GraphQL schema.
See the express-graphql tutorial for sample usage.
See the GitHub README for more extensive documentation of the details of this method.