Robin Wieruch - The Road to GraphQL: Your journey to master pragmatic GraphQL in JavaScript with React.js and Node.js

The central theme of this book is GraphQL in modern applications. While GraphQL is only a specification that can be used in many programming languages, this book focuses on GraphQL in JavaScript. Facebook, the company behind the GraphQL specification, released GraphQLs reference implementation in JavaScript, and for good reason: JavaScript is currently the most compelling programming language and ecosystem for companies and their client-server architecture.

GraphQL is a query language that can be used anywhere, but it often bridges the gap between client and server applications. It isnt opinionated about which network layer is used, so data can be read and written between client and server applications. It is used to complement the network stack for many libraries and frameworks in JavaScript. The client side takes advantage of popular solutions like React, Angular, and Vue, while the server side can use middleware libraries like Express, Koa, and Hapi in a Node.js environment. It is just a matter of sending GraphQL operations with HTTP across the wire to connect both sides.

The emergence of GraphQL introduces a new era in web development. RESTful applications were the industry favorite for data transfers between client and server applications, but modern requirements have shifted. Applications have to deal with multiple clientsi.e. desktop, web, mobile, wearableswhich are all interested in APIs exposed by server applications. The choice becomes one between using multiple client-specific APIs with REST, or just one API with GraphQL for all client applications, which hardly seems like a choice at all. GraphQL is more than just a unified interface, though; its ecosystem offers powerful capabilities and even more potential as its open source community grows.

For me, it was a lucky coincidence that a former coworker open-sourced the GraphQL implementation for Java. He worked to become one of GraphQLs first open source contributors, eventually creating the go-to implementations for Java. The experience shaped my own thinking about GraphQL, which was expanded when my employer evaluated GraphQL for their enterprise application. The glue between our client and server application was initially largely influenced by REST; we had API endpoints for all our RESTful resources in place, eventually running into issues like Facebook for API-consuming client-side applications. The API endpoints were too rigid, so they required aggregations and modifications. An aggregation means putting resources into a singular API endpoint, where a modification is to offer variations of an API endpoint to request different representations of a resource. We introduced our own implementation to request resources from the server and ended up with our own naive implementation of GraphQL. From a client-side perspective, only Relay for React was released those days as a sophisticated library in terms of consuming GraphQL APIs, so we invested time in this as well. In the end, GraphQL was too early in its development, so we postponed introducing it to our technology stack. Admittedly, none of us knew it would become so powerful or popular.

This book starts with GraphQL in client-side applications, so you will use React as a UI library to consume a third-party GraphQL API, which happens to be GitHubs GraphQL API. It is a popular choice among developers for a couple reasons: GitHub was one of few popular companies to release a GraphQL API to the public; GitHubs subsequent growth has granted some credibility to GraphQL itself; and a third-party API usually focuses on client-side GraphQL application in the beginning. This book teaches how to consume the GraphQL API in a client application without having to build the GraphQL server yourself.

When we shift gears in this book toward GraphQL on the server side, we will implement a GraphQL API that can eventually be consumed by a GraphQL client application. You will implement powerful features such as authentication, database connections and pagination. By the end, you should have a firm grasp about using GraphQL in your JavaScript applications.