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Object-Oriented JavaScript - Third Edition

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

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Product type Book
Published in Jan 2017
Publisher Packt
ISBN-13 9781785880568
Pages 550 pages
Edition 3rd Edition
Languages
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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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Table of Contents (25) Chapters Close

Object-Oriented JavaScript - Third Edition
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
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 Reserved Words Built-in Functions
Built-in Objects Regular Expressions
Answers to Exercise Questions

Parasitic inheritance


If you like the fact that you can have all kinds of different ways to implement inheritance in JavaScript and you're hungry for more, here's another one. This pattern, courtesy of Douglas Crockford, is called parasitic inheritance. It's about a function that creates objects by taking all the functionality from another object into a new one, augmenting the new object, and returning it, pretending that it has done all the work.

Here's an ordinary object, defined with an object literal, and unaware of the fact that it's soon going to fall victim to parasitism:

    var twoD = { 
      name: '2D shape', 
      dimensions: 2 
    }; 

A function that creates triangle objects could:

  • Use the twoD object as a prototype of an object called that (similar to this for convenience). This can be done in any way you saw previously, for example, using the object() function or copying all the properties.

  • Augment that with more properties.

  • Return that:

            function triangle...
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