JavaScript: The New Toys begins with a high-level list of the new features of JavaScript in “ES2015” and “ES2016,” along with a discussion of the new process by which new features are added to the language, who’s responsible, how to keep track of what’s coming, and how to get involved. Setup information comes next as not all JavaScript environments have the new features yet. After that the bulk of the book covers point-by-point “just the facts” coverage of the new features, along with recommendations for how old habits can be updated to take advantage of them. In those chapters, when introducing a new feature, we open with examples of the problems it helps solve, then explore how the new feature solves them and the details (without getting too academic) of how it works. We end with a brief look ahead ES2017 and ES2018. Four key topics amongst the coverage are: New let and const declarations: Why they’re useful, how to use them, some non-obvious things they do for us. Classes: What problems they solve, how they work, how they both are and are not new, syntax details. Arrow functions and lexical this: Why we want to use them, how to use them, details of how they work. Promises: What they do for us, how to use them, some common pitfalls, technical details. In all cases, source code will primarily be fairly brief examples demonstrating the syntax and behavior of the features being discussed.
Author: T. J. Crowder