index.js

// "apollo-server" is a pretty awesome package 📦.
// It has bindings for Express, Hapi, serverless, and many other frameworks.
// It has some nice defaults and is the defacto standard for Node-based APIs as of 2019.
// It will include an IDE called GraphQL Playground for testing queries.
// To read more about it, seehttps://www.apollographql.com/docs/apollo-server/
// ⚡
const { ApolloServer, gql } = require('apollo-server');

// "typeDefs" is your GraphQL schema.
//
// In this example, we have a single type.
// As you can imagine, you'll eventually have LOTS of schema types, enums, etc.
//
// These can be merged by hand using something like lodash, or safely merged using ASTs.
// `merge-graphql-schemas` is good at this.
// You can give it a directory and it will merge all of your schema files for you.
const typeDefs = gql`
  # You can add single line comments
  type Query {
    """
    Or multi-line comments w/ markdown! ![doge](https://media0.giphy.com/media/aFTt8wvDtqKCQ/giphy.gif)
    """
    hello: String
  }
`;

// Resolvers are functions that map 1-to-1 with your GraphQL schema.
// Every type and field in your schema has a resolver function.
//
// If you think of a GraphQL query as a tree, resolvers are executed from top
// to bottom and it will execute adjacent fields in parallel.
//
// If you don't specify a resolver, the runtime provides a default one that tries
// to resolve it itself by grabbing the property from "rootObj".
//
// Every resolver has the same function signature.
// We refer to it as "RACI", which is "root", "args", "context", "info"
// "root" is an Object passed from parent types to child fields
// "args" is an Object that contains arguments (Ex: "name" in the case below)
// "context" is an Object of common properties shared between all resolvers
// "info" is an Object containing information about the GraphQL query
//
// Resolvers can be sync or async. They can resolve values from an API, cache, etc.
const resolvers = {
  Query: {
    hello: (root, args, context) => 'Hello world!',
  },
};

// At startup, the GraphQL runtime needs a handle on your schema and
// resolver functions.  This gets interesting when you can fetch schemas
// remotely, mutate them, and pass them off to your server.
//
// The ApolloServer instance accepts many other options that are useful
// when you want to make your server production-ready.
//
// Google "GraphQL schema stitching" if you're interested.
const server = new ApolloServer({
  typeDefs,
  resolvers,
});

// Hello world!
server.listen().then(({ url }) => {
  console.log(`🚀 Server ready at ${url}`);
});