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Object-Oriented JavaScript - Second Edition

You're reading from   Object-Oriented JavaScript - Second Edition If you've limited or no experience with JavaScript, this book will put you on the road to being an expert. A wonderfully compiled introduction to objects in JavaScript, it teaches through examples and practical play.

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Product type Paperback
Published in Jul 2013
Publisher Packt
ISBN-13 9781849693127
Length 382 pages
Edition 2nd Edition
Languages
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Toc

Table of Contents (14) Chapters Close

Preface 1. Object-oriented JavaScript FREE CHAPTER 2. Primitive Data Types, Arrays, Loops, and Conditions 3. Functions 4. Objects 5. Prototype 6. Inheritance 7. The Browser Environment 8. Coding and Design Patterns A. Reserved Words B. Built-in Functions
C. Built-in Objects D. Regular Expressions
Index

Uber – access to the parent from a child object


Classical OO languages usually have a special syntax that gives you access to the parent class, also referred to as superclass. This could be convenient when a child wants to have a method that does everything the parent's method does plus something in addition. In such cases, the child calls the parent's method with the same name and works with the result.

In JavaScript, there is no such special syntax, but it's trivial to achieve the same functionality. Let's rewrite the last example and, while taking care of inheritance, also create an uber property that points to the parent's prototype object.

function Shape() {}
// augment prototype
Shape.prototype.name = 'Shape';
Shape.prototype.toString = function () {
varconst = this.constructor;
returnconst.uber
    ? this.const.uber.toString() + ', ' + this.name
    : this.name;
};

function TwoDShape() {}
// take care of inheritance
var F = function () {};
F.prototype = Shape.prototype;
TwoDShape.prototype...
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