03. Anonymous Functions

Conventional functions come with a name linked to its procedure. Anonymous functions, however, don't have a name.

Furthermore, the function is not processed until the statement which it is attached to is declared.

var area = function(width, height) {
  return width * height;
};  // Anonymous function
 
var size = area(3, 4);

Anonymous Functions as Closures

A closure is a function that is passed into another function as an argument.

setTimeout(function() {
  alert("Hello world!");
}, 1000);

The setTimeout function will wait 1000 ms, then send an alert out to the user, displaying "Hello world!" This is an example of an anonymous funciton that is passed into a method as a closure.

Immediately invoked function expressions (IIFE)

Immediately Invoked Function Expressions (IIFE) pronounced iffy are executed once as the interpreter comes across them. These functions are used for a block of code that needs to be run only once.

var area = (function(n) {
  return (n < 1) ? 1 : factorial(n-1) * n;
}(5));

Build modern and responsive webpages

High Performance Web Sites

Build modern and responsive webpages Try Front-end

Want your web site to display more quickly? This book presents 14 specific rules that will cut 25% to 50% off response time when users request a page. Author Steve Souders, in his job as Chief Performance Yahoo!, collected these best practices while optimizing some of the most-visited pages on the Web.

$ Check price
29.9929.99Amazon 4.5 logo(63+ reviews)

More Front-end resources

Aching back from coding all day?

Prism Glasses

Aching back from coding all day? Try Back Problems

Ever feel achy from sitting crunched up on your computer table? Try lying down with these optical glasses that allow you to work on your laptop while lying flat on your back. This is the perfect solution with those with limited mobility or those who wish to prevent neck cramps and back strains.

$ Check price
4.454.45Amazon 4 logo(128+ reviews)

More Back Problems resources

Ad