constructing_types_programmatically.js

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


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