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

Lexical this in arrow functions


We discussed ES6 arrow functions and the syntax in detail in the last chapter. However, an important aspect of arrow functions is that they behave differently from normal functions. The difference is subtle but important. Arrow functions do not have their own value of this. The value of this in an arrow function is inherited from the enclosing (lexical) scope.

Functions have a special variable this that refers to the object via which the method was invoked. As the value of this is dynamically given based on the function invocation, it is sometimes called dynamic this. A function is executed in two scopes-lexical and dynamic. A lexical scope is a scope that surrounds the function scope, and the dynamic scope is the scope that called the function (usually an object)

In JavaScript, traditional functions play several roles. They are non-method functions (aka subroutines or functions), methods (part of an object), and constructors. When functions do the duty of a...