[GraphQL] Write a GraphQL Schema in JavaScript

Writing out a GraphQL Schema in the common GraphQL Language can work for simple GraphQL Schemas, but as our application grows, or when we start using more complex types like interfaces or unions, we find that we can’t use a GraphQL Language file in the same way as before. In this video, we’ll learn how to translate a GraphQL Schema written in GraphQL into a GraphQL Schema written in JavaScript.

const express   = require('express');
const graphqlHttp = require('express-graphql');

const server = express();
const port   = process.env.PORT || 3000;

const {
    GraphQLSchema,
    GraphQLObjectType,
    GraphQLString,
    GraphQLInt,
    GraphQLBoolean,
    GraphQLID
      } = require('graphql');

const videoType = new GraphQLObjectType({
    name: 'video',
    description: 'A video on Egghead.io',
    fields: {
        id: {
            type: GraphQLID,
            description: 'The id of the video'
        },
        title: {
            type: GraphQLString,
            description: 'The title of the video'
        },
        duration: {
            type: GraphQLInt,
            description: 'The duration of the video'
        },
        watched: {
            type: GraphQLBoolean,
            description: 'Whether or no the viewer watched the video'
        }
    }
})

const queryType = new GraphQLObjectType({
    name: 'QueryType',
    description: 'The root query type',
    fields :{
        video: {
            type: videoType,
            resolve: () => {
                return new Promise((resolve) => {
                    resolve({
                        id: 'a',
                        title: 'GraphQL',
                        duration: 180,
                        watched: false })
                })
            }
        }
    }
});

const schema = new GraphQLSchema({
    query: queryType
});

/*
const schema = buildSchema(`
    type Video {
        id: ID,
        title: String,
        duration: Int,
        watched: Boolean
    }
    
    type Query {
        video: Video,
        videos: [Video]
    }
    
    type Schema{
        query: Query
    }
`);

const videos = [
    {
        id       : '1',
        title    : 'react',
        duration : 180,
        watched  : true
    },
    {
        id       : '2',
        title    : 'relay',
        duration : 230,
        watched  : false
    }
];

const resolvers = {
    video  : () => ({
        id       : '1',
        title    : 'bar',
        duration : 180,
        watched  : true
    }),
    videos : () => videos
};*/

server.use('/graphql', graphqlHttp({
                                     schema,
                                     graphiql  : true, // use graphiql interface
                                 }));

server.listen(port, () => {
    console.log(`Listening on http`)
})