基本类型

var express = require("express")
var { createHandler } = require("graphql-http/lib/use/express")
var { buildSchema } = require("graphql")

// Construct a schema, using GraphQL schema language
var schema = buildSchema(`
  type Query {
    quoteOfTheDay: String
    random: Float!
    rollThreeDice: [Int]
  }
`)

// The root provides a resolver function for each API endpoint
var root = {
  quoteOfTheDay: () => {
    return Math.random() < 0.5 ? "Take it easy" : "Salvation lies within"
  },
  random: () => {
    return Math.random()
  },
  rollThreeDice: () => {
    return [1, 2, 3].map(_ => 1 + Math.floor(Math.random() * 6))
  },
}

var app = express()
app.all(
  "/graphql",
  createHandler({
    schema: schema,
    rootValue: root,
  })
)
app.listen(4000)
console.log("Running a GraphQL API server at localhost:4000/graphql")