Test-Driven JavaScript Development

Chapter 6. Applied Functions and Closures

In the previous chapter we discussed the theoretical aspects of JavaScript functions, familiarizing ourselves with execution contexts and the scope chain. JavaScript supports nested functions, which allows for closures that can keep private state, and can be used for anything from ad hoc scopes to implementing memoization, function binding, modules and stateful functions, and objects.

In this chapter we will work through several examples of how to make good use of JavaScript functions and closures.

6.1 Binding Functions

When passing methods as callbacks, the implicit this value is lost unless the object on which it should execute is passed along with it. This can be confusing unless the semantics of ...