GraphQL very basic example.

app.js

const express = require('express');
const graphqlHTTP = require('express-graphql');
const { buildSchema } = require('graphql');
const app = express();
let updatedCount = 0;
let updatedDate  = new Date();

class GetCount{
  constructor(){
    this.counter = updatedCount;
    this.date = new Date();
  }
}
const schema = buildSchema(`
  input Count{
    counter: Int!
  }
  type GetCount{
    counter: Int!
    updatedDate: String!
  }
  type Query {
    getCount: GetCount
  }
  type Mutation{
    updateCounter(input: Count): GetCount
  }
`)
const rootValue = {
  getCount: ( ) => new GetCount(),
  updateCounter: ({input}) => {
    updatedCount = updatedCount + input.counter;
    return new GetCount();
  }
}
app.use('/graphQl',graphqlHTTP({
  graphiql: true,
  schema,
  rootValue
}))
app.listen(3000,()=> console.log('hey!'));

var express = require('express');
var graphqlHTTP = require('express-graphql');
var { buildSchema } = require('graphql');

var app = express();

const names = ["default"];

class DoSometing{
constructor(){
this.all = names.toString();
}
}

const schema = buildSchema(`
input Name{
name: String!
}

type DoSometing{
    all : String!
}

type Query{
    getNames: DoSometing
}

type Mutation{
    addName(input: Name): DoSometing
}

`)

const rootValue = {
addName: ({input}) =>{
names.push(input.name);
return new DoSometing();
},
getNames: () => new DoSometing(),
}

app.use('/graphql',graphqlHTTP({
graphiql: true,
schema,
rootValue
}))

app.listen(4000, () => console.log('Now browse to localhost:4000/graphql'));