How to write GraphQL Resolvers properly?

Question

So the GraphQL site has S#*t documentation as far as I can tell on nested queries like user spesifics and its driving me nuts (I seriously want to pull me hair out right now). Can someone please explain to me how revolvers work and why what I'm doing isn't working?

PROBLEM: I have created the following index.js file for my GraphQL API:

var express = require('express');
var graphqlHTTP = require('express-graphql');
var { buildSchema } = require('graphql');

// Define Schemas
var schema = buildSchema(`
    type Query {
        user: User
    }
    type User {
        firstName: String
        lastName: String
        email: String
        socialMedia: SOCIALMEDIA
    }
    type SOCIALMEDIA {
        facebook: String
        instagram: String
        twitter: String
    }
`);

// Define resolver functions
var root = {
    User: {
        firstName: () => 'John',
        lastName: () => 'Doe',
        email: () => 'John.Doe@gmail.com'
    },
    SOCIALMEDIA: {
        facebook: () => 'John Doe Facebook',
        instagram: () => 'John Doe Instagram',
        twitter: () => 'John Doe Twitter'
    }

 };

var app = express();
app.use('/', graphqlHTTP({
    schema: schema,
    rootValue: root,
    graphiql: true,
}));
app.listen(8080, () => console.log('Now browse to localhost:8080'));

And despite my best efforts, when I submit the following query:

{
  user {
    firstName
  }
}

I get the following answer:

{
  "data": {
    "user": null
  }
}

Why is it null?!?! I haven't even tried to get fancy with user(id: $ID): [User] iterations or anything resembling passing in arguments or functions even and its already giving me stick!

What am I missing about how nested fields work?

EDIT: wow... ok got it working?

user: () => ({
        firstName: 'John',
        lastName: 'Doe',
        email: 'John.Doe@gmail.com',
        socialMedia: {
            facebook: 'John Doe Facebook',
            instagram: 'John Doe Instagram',
            twitter: 'John Doe Twitter'
        }
    }),

Whats the hard-and-fast rule for this nonsense??

Answer 1

Try this,

// Define Schemas
var schema = buildSchema(`
    type Query {
        getUser: User
        getSocialMedia: SOCIALMEDIA
    }
    type User {
        firstName: String
        lastName: String
        email: String
        socialMedia: SOCIALMEDIA
    }
    type SOCIALMEDIA {
        facebook: String
        instagram: String
        twitter: String
    }
`);

// Define resolver functions
var root = {
    getUser: {
        firstName: () => 'John',
        lastName: () => 'Doe',
        email: () => 'John.Doe@gmail.com',
        socialMedia: {
          facebook: () => 'John Doe Facebook',
          instagram: () => 'John Doe Instagram',
          twitter: () => 'John Doe Twitter'
        }
    },
    getSocialMedia: {
        facebook: () => 'John Doe Facebook',
        instagram: () => 'John Doe Instagram',
        twitter: () => 'John Doe Twitter'
    }

 };