2 FAQ: book and supplementary material

This chapter answers questions you may have and gives tips for reading this book.

2.1 How to read this book

2.1.1 Isn’t this book too long for impatient programmers?

This book is three books in one:

• You can use it to get started with JavaScript as quickly as possible. This “mode” is for impatient people:
  • Start reading with §5 “The big picture”.
  • Skip all chapters and sections marked as “advanced”, and all quick references.
• It gives you a comprehensive look at current JavaScript. In this “mode”, you read everything and don’t skip advanced content and quick references.
• It serves as a reference. If there is a topic that you are interested in, you can find information on it via the table of contents or via the index. Due to basic and advanced content being mixed, everything you need is usually in a single location.

The quizzes and exercises (see §9 “Getting started with quizzes and exercises”) play an important part in helping you practice and retain what you have learned.

2.1.2 Why are some chapters and sections marked with “(advanced)”?

Several chapters and sections are marked with “(advanced)”. The idea is that you can initially skip them. That is, you can get a quick working knowledge of JavaScript by only reading the basic (non-advanced) content.

As your knowledge evolves, you can later come back to some or all of the advanced content.

2.1.3 Why are some chapters marked with “(bonus)”?

The bonus chapters are only available in the paid versions of this book (print and ebook). They are listed in the full table of contents.

2.2 Purchases and support

2.2.1 How do I submit feedback and corrections?

The HTML version of this book (online, or ad-free archive in paid version) has a link at the end of each chapter that enables you to give feedback.

2.2.2 How do I get updates for the downloads I bought at Payhip?

• The receipt email for the purchase includes a link. You’ll always be able to download the latest version of the files at that location.

• If you opted into emails while buying, then you’ll get an email whenever there is new content. To opt in later, you must contact Payhip (see bottom of payhip.com).

2.3 Notations and conventions

2.3.1 What is a type signature? Why am I seeing static types in this book?

For example, you may see:

Number.isFinite(num: number): boolean

That is called the type signature of Number.isFinite(). This notation, especially the static types number of num and boolean of the result, are not real JavaScript. The notation is borrowed from the compile-to-JavaScript language TypeScript (which is mostly just JavaScript plus static typing).

Why is this notation being used? It helps give you a quick idea of how a function works. The notation is explained in detail in a 2ality blog post, but is usually relatively intuitive.

2.3.2 What do the notes with icons mean?