A one-stop reference for the latest JavaScript features and techniques JavaScript: The New Toys explores the newest features of the world's most popular programming language while also showing you how to track what's coming and get involved. Author T.J. Crowder, the top JavaScript contributor on Stack Overflow, walks you through the significant changes and additions to the language along with key tools and techniques to help you get up to date with modern JavaScript. Beginning with a high-level overview of new features, you'll learn what's new, how new features come about, who's responsible, how to stay on top of what's coming next, and how to use new features even in old browsers. The bulk of the coverage consists of point-by-point "just the facts" explanations of each new feature, plus expert recommendations for tweaking old habits to integrate new techniques. Each feature is introduced with the problem it solves and the details of how it works including brief source code demonstrating syntax and behavior. With comprehensive coverage of the new features and techniques, this book provides an invaluable resource for web programmers everywhere. Modern JavaScript is a fast-changing language, both in terms of what's officially specified and what browsers support at any given time. This book addresses all of the new and updated features of ES2015 and ES2016 plus the finalized features of ES2017 so far. * Discover the unexpected advantages of the new let and const declarations * Learn how classes solve common problems, and get details on syntax * Delve into the use and mechanics of arrow functions and lexical this * Adopt new best practices for using Promises, and avoid common pitfalls All major browsers support JavaScript, but support for individual functions and releases is all over the map. JavaScript: The New Toys shows you what's new, how to use it, but how to keep incomplete browser support from holding you back.