Book Image

Node Cookbook - Third Edition

By : David Mark Clements, Mathias Buus Madsen, Peter Elger, Matteo Collina
Book Image

Node Cookbook - Third Edition

By: David Mark Clements, Mathias Buus Madsen, Peter Elger, Matteo Collina

Overview of this book

Today's web demands efficient real-time applications and scalability. Asynchronous event-driven programming is ideal for this, and this is where Node.js comes in. Server-side JavaScript has been here since the 90s, but Node got it right. With Node for tooling and server-side logic, and a browser-based client-side UI, everything is JavaScript. This leads to rapid, fluid development cycles. The full-stack, single language experience means less context-switching between languages for developers, architects and whole teams. This book shows you how to build fast, efficient, and scalable client-server solutions using the latest versions of Node. The book begins with debugging tips and tricks of the trade, and how to write your own modules. Then you'll learn the fundamentals of streams in Node.js, discover I/O control, and how to implement the different web protocols. You'll find recipes for integrating databases such as MongoDB, MySQL/MariaDB, Postgres, Redis, and LevelDB. We also cover the options for building web application with Express, Hapi and Koa. You will then learn about security essentials in Node.js and advanced optimization tools and techniques. By the end of the book you will have acquired the level of expertise to build production-ready and scalable Node.js systems. The techniques and skills you will learn in this book are based on the best practices developed by nearForm, one of the leaders in Node implementations, who supported the work of the authors on this book.
Table of Contents (12 chapters)

Creating a Koa web app

Koa is an evolution of the middleware concept in line with updates to the JavaScript language. Originally in Koa-v1, flow control was handled by re-purposing ECMAScript 2015 (ES6) Generator functions (using the yield keyword to freeze function execution) combined with promises. In Koa-v2, a more normative route is taken using ES 2016 async/await syntax.

It's a minimalist web framework compared to Express (and far more minimalist compared to Hapi). Koa is more closely comparable to the Connect web framework (which was the precursor to Express). This means that functionality that tends to come as standard in other web frameworks (such as route handling) is installed separately as Koa middleware.

In this recipe, we're going to create a Koa (v2) web application.

Node 8+ Only
This recipe focuses on Koa-v2, using up-to-date async/await syntax, which is...