welcome

The world of JavaScript has changed a great deal in the years since the second edition Secrets of the JavaScript Ninja was released. Back in those days, ES6 (later renamed ES2015) was cutting-edge, a breath of fresh air for a language that had stagnated for years. React, ESLint, and TypeScript were all in their infancy. Most websites still used jQuery, the groundbreaking framework created by John Resig, author of the first edition.

What I’ve always loved about Secrets of the JavaScript Ninja is the way it explains concepts from the ground up in a way that’s accessible to beginners and clarifying for experienced developers. I’ve set out to write a new edition that retains that spirit while covering topics that are relevant to today’s engineers.

As with previous editions, the book’s focus is on developing a deep understanding of JavaScript language features and concepts. You’ll learn about the distinction between function declarations and function expressions, the connection between classes and prototypes, and how “async” functions work in a single-threaded language. Along the way, you’ll be introduced to relevant tools that can help you catch bugs early and keep your code tidy.