server.js

import { GraphQLServer } from 'graphql-yoga'

const typeDefs = `
  type Query {
    hello: String!
  }
`

const resolvers = {
  Query: {
    hello: () => `Hello World`,
  },
}

const server = new GraphQLServer({ typeDefs, resolvers })
server.start(() => console.log('Server is running on localhost:4000'))