Mastering JavaScript

Functions, Closures, and Modules
Anonymous functions
We introduced you to anonymous functions a bit earlier in this chapter, and as they're
a crucial concept, we will take a detailed look at them. For a language inspired by
Scheme, anonymous functions are an important logical and structural construct.
Anonymous functions are typically used in cases where the function doesn't need
to have a name for later reference. Let's look at some of the most popular usages of
anonymous functions.
Anonymous functions while creating an object
An anonymous function can be assigned to an object property. When we do that,
we can call that function with a dot (.) operator. If you are coming from a Java or
other OO language background, you will find this very familiar. In such languages,
a function, which is part of a class is generally called with a notation—Class.
function(). Let's consider the following example:
var santa = {
say :function(){
console.log("ho ho ho");
}
}
santa.say();
In this example, we are creating an object with a say property, which is an
anonymous function. In this particular case, this property is known as a method and
not a function. We don't need to name this function because we are going to invoke it
as the object property. This is a popular pattern and should come in handy.
Anonymous functions while creating a list
Here, we are creating two anonymous functions and adding them to an array. (We
will take a detailed look at arrays later.) Then, you loop through this array and
execute the functions in a loop:
var things = [
function() { alert("ThingOne") },
function() { alert("ThingTwo") },
];
for(var x=0; x