构建类型

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

var schema = buildSchema(`
  type User {
    id: String
    name: String
  }

  type Query {
    user(id: String): User
  }
`)

// Maps id to User object
var fakeDatabase = {
  a: {
    id: "a",
    name: "alice",
  },
  b: {
    id: "b",
    name: "bob",
  },
}

var root = {
  user: ({ id }) => {
    return fakeDatabase[id]
  },
}

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")

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

// Maps id to User object
var fakeDatabase = {
  a: {
    id: "a",
    name: "alice",
  },
  b: {
    id: "b",
    name: "bob",
  },
}

// Define the User type
var userType = new graphql.GraphQLObjectType({
  name: "User",
  fields: {
    id: { type: graphql.GraphQLString },
    name: { type: graphql.GraphQLString },
  },
})

// Define the Query type
var queryType = new graphql.GraphQLObjectType({
  name: "Query",
  fields: {
    user: {
      type: userType,
      // `args` describes the arguments that the `user` query accepts
      args: {
        id: { type: graphql.GraphQLString },
      },
      resolve: (_, { id }) => {
        return fakeDatabase[id]
      },
    },
  },
})

var schema = new graphql.GraphQLSchema({ query: queryType })

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