Chapter 2. Functions, Closures, and Modules

In the previous chapter, we deliberately did not discuss certain aspects of JavaScript. These are some of the features of the language that give JavaScript its power and elegance. If you are an intermediate- or advanced-level JavaScript programmer, you may be actively using objects and functions. In many cases, however, developers stumble at these fundamental levels and develop a half-baked or sometimes wrong understanding of the core JavaScript constructs. There is generally a very poor understanding of the concept of closures in JavaScript, due to which many programmers cannot use the functional aspects of JavaScript very well. In JavaScript, there is a strong interconnection between objects, functions, and closures. Understanding the strong relationship between these three concepts can vastly improve our JavaScript programming ability, giving us a strong foundation for any type of application development.

Functions are fundamental...