Book Image

Object-Oriented JavaScript - Third Edition

By : Stoyan STEFANOV, Antani
5 (1)
Book Image

Object-Oriented JavaScript - Third Edition

5 (1)
By: Stoyan STEFANOV, Antani

Overview of this book

JavaScript is an object-oriented programming language that is used for website development. Web pages developed today currently follow a paradigm that has three clearly distinguishable parts: content (HTML), presentation (CSS), and behavior (JavaScript). JavaScript is one important pillar in this paradigm, and is responsible for the running of the web pages. This book will take your JavaScript skills to a new level of sophistication and get you prepared for your journey through professional web development. Updated for ES6, this book covers everything you will need to unleash the power of object-oriented programming in JavaScript while building professional web applications. The book begins with the basics of object-oriented programming in JavaScript and then gradually progresses to cover functions, objects, and prototypes, and how these concepts can be used to make your programs cleaner, more maintainable, faster, and compatible with other programs/libraries. By the end of the book, you will have learned how to incorporate object-oriented programming in your web development workflow to build professional JavaScript applications.
Table of Contents (19 chapters)
15
B. Built-in Functions
17
D. Regular Expressions

Functions are data


Functions in JavaScript are actually data. This is an important concept that we'll need later on. This means that you can create a function and assign it to a variable, as follows:

    var f = function () { 
      return 1; 
    }; 

This way of defining a function is sometimes referred to as function literal notation.

The function () { return 1;} part is a function expression. A function expression can optionally have a name, in which case it becomes a named function expression (NFE). So, this is also allowed, although rarely seen in practice (and causes IE to mistakenly create two variables in the enclosing scope-f and myFunc):

    var f = function myFunc() { 
      return 1; 
    }; 

As you can see, there's no difference between a named function expression and a function declaration. But they are, in fact, different. The only way to distinguish between the two is to look at the context in which they are used. Function declarations may only...