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Object-Oriented JavaScript

You're reading from   Object-Oriented JavaScript Learn everything you need to know about object-oriented JavaScript (OOJS)

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Product type Paperback
Published in Jan 2017
Publisher Packt
ISBN-13 9781785880568
Length 550 pages
Edition 3rd Edition
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Authors (2):
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Stoyan STEFANOV Stoyan STEFANOV
Author Profile Icon Stoyan STEFANOV
Stoyan STEFANOV
Ved Antani Ved Antani
Author Profile Icon Ved Antani
Ved Antani
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Toc

Table of Contents (19) Chapters Close

Preface 1. Object-Oriented JavaScript FREE CHAPTER 2. Primitive Data Types, Arrays, Loops, and Conditions 3. Functions 4. Objects 5. ES6 Iterators and Generators 6. Prototype 7. Inheritance 8. Classes and Modules 9. Promises and Proxies 10. The Browser Environment 11. Coding and Design Patterns 12. Testing and Debugging 13. Reactive Programming and React A. Reserved Words B. Built-in Functions
C. Built-in Objects D. Regular Expressions
E. Answers to Exercise Questions

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...

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