GraphQL API Server sample. refs http://graphql.org/code/#javascript

server.js

// http://graphql.org/code/#javascript
var express = require('express');
var graphqlHTTP = require('express-graphql');
var { buildSchema } = require('graphql');

var schema = buildSchema(`
  type Shop {
    id: ID!
    name: String!
    station: String
    score: Int
  }
  type Blog {
    id: Int!
    name: String!
    url: String!
    title: String!
  }
  type Query {
    hello: String
    game: [String]
    shops: [Shop]!
    blogs(id:Int, name:String): [Blog]!
  }
`);

// The root provides a resolver function for each API endpoint
var root = {
  hello: () => {
    return 'Hello world!';
  },
  game: () => {
    return ['ゲームならIngressをやりましょう!!', 'もしくはPokémon GOでもいいですよ!!'];
  },
  shops: () => {
    return [
      {id: 1, name:'吉村家', station:'横浜駅', score:100 },
      {id: 2, name:'武蔵家　日吉店', station:'日吉駅',score:90 },
      {id: 3, name:'桂家', station:'方南町駅',score:95 },
      {id: 4, name:'ラーメン大桜　向ヶ丘遊園店', station:'向ヶ丘遊園駅',score:90 },
      {id: 5, name:'横浜家系 侍 渋谷店', station:'渋谷駅',score:75 },
    ];
  },
  blogs: (params) => {
    console.log(params);
    var blogs = [
      {id:1, name:'info', url:'http://info.seesaa.net/', title:'Seesaaからのお知らせ' },
      {id:2, name:'faq', url:'http://faq.seesaa.net/', title:'Seesaaブログ ヘルプセンター' },
      {id:3, name:'customrecipe', url:'http://customrecipe.seesaa.net/', title:'Seesaaブログカスタムレシピ' },
      {id:4, name:'ramen-diary', url:'http://ramen-diary.seesaa.net/', title:'らーめん日記' },
    ];
    if (Object.keys(params).length > 0) {
      return blogs.filter(function(rec){
        if (typeof params.id != 'undefined') return params.id == rec.id;
        if (typeof params.name != 'undefined') return params.name == rec.name;
      });
    } else {
      return blogs;
    }
  }
};

var app = express();
app.use('/graphql', graphqlHTTP({
  schema: schema,
  rootValue: root,
  graphiql: true,
}));
app.listen(4000);
console.log('Running a GraphQL API server at localhost:4000/graphql');