Chapter 1, Understanding the Node Environment, gives a brief description of the particular problems Node attempts to solve, their history and roots in the Unix design philosophy, and Node's power as a systems language. We will also learn how to write optimized, modern JavaScript on V8 (the engine powering Node), including a brief tour of the newest features of the language that will help you upgrade your code.
Chapter 2, Understanding Asynchronous Event-Driven Programming, digs deep into the fundamental characteristics of Node's design: event-driven, asynchronous programming. By the end of this chapter, you will understand how events, callbacks, and timers are used in Node as well as how the event loop works to enable high-speed I/O across filesystems, networks, and processes. We'll also learn about modern concurrency modeling constructs, from the default Node callback pattern to Promises, Generators, async/await, and other flow control techniques.
Chapter 3, Streaming Data Across Nodes and Clients, describes how streams of I/O data are knitted through most network software, emitted by file servers or broadcast in response to an HTTP GET request. Here, you will learn how Node facilitates the design, implementation, and composition of network software, using examples of HTTP servers, readable and writable file streams, and other I/O focused Node modules and patterns. You will take a deep dive into the Streams implementation, mastering this fundamental part of the Node stack.
Chapter 4, Using Node to Access the Filesystem, lays out what you need to know when accessing the filesystem with Node, how to create file streams for reading and writing, along with techniques for handling file uploads and other networked file operations. You will also implement a simple file browsing application using Electron.
Chapter 5, Managing Many Simultaneous Client Connections, shows you how Node helps in solving problems accompanying the high-volume and high-concurrency environments that contemporary, collaborative web applications demand. Through examples, learn how to efficiently track user state, route HTTP requests, handle sessions, and authenticate requests using the Redis database and Express web application framework.
Chapter 6, Creating Real-Time Applications, explores AJAX, Server-Sent-Events, and the WebSocket protocol, discussing their pros and cons when building real-time systems, and how to implement each using Node. We finish the chapter by building a collaborative document editing application.
Chapter 7, Using Multiple Processes, teaches how to distribute clusters of Node processes across multicore processors, and other techniques for scaling Node applications. An investigation of the differences between programming in single and multithreaded environments leads to a discussion on how to spawn, fork, and communicate with child processes in Node, including a section on using the PM2 process manager. We also build an analytics tool that records, and displays, the mouse actions of multiple, simultaneous clients connected through a cluster of web sockets.
Chapter 8, Scaling Your Application, outlines some techniques for detecting when to scale, deciding how to scale, and scaling Node applications across multiple servers and cloud services, with examples, including how to use RabbitMQ as a message queue, using NGINX to proxy Node servers, and using Amazon Web Services in your application. The chapter closes with us building a robust customer service application deployed on Heroku, where you will learn how to use the Twilio SMS gateway with Node.
Chapter 9, Microservices, introduces the concept of microservices—small, independent services—and how we got from monolithic and 3-Tier stacks to large fleets of independent services whose collaboration patterns are dynamic. We'll learn how to use Seneca and Node to create an autodiscovering services mesh, AWS Lambda to create serverless applications infinitely scalable in the cloud, and finally, how to create Docker containers and orchestrate their deployment with Kubernetes.
Chapter 10, Testing Your Application, explains how to implement unit, functional, and integration tests with Node. We will go deep, exploring how to use native debugging and testing modules, heap dumps and CPU profiling, eventually building test suites with Mocha and Chai. We'll cover mocks, stubs, and spies with Sinon, live debugging of running Node processes with Chrome DevTools, and how to use tools like Puppeteer to implement headless testing of your UI code.
Appendix A, Organizing Your Work into Modules, gives tips on using the npm package management system. Here, you will learn how to create, publish, and manage packages.
Appendix B, Creating your own C++ Add-ons, provides a brief introduction on how to build your own C++ add-ons and how to use them from within Node. We also cover the new NAN (Native Abstractions for Node) tool and how that can help you with writing cross-platform, future-proofed add-ons.