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

Object properties and attributes

Each object has a few properties. Each property, in turn, has a key and attributes. A property's state is stored in these attributes. All properties have the following attributes:

  • Enumerable (boolean): This indicates if you can enumerate the properties of the object. System properties are non-enumerable while user properties are enumerable. Unless there is a strong reason, this property should remain untouched.
  • Configurable(boolean): If this attribute is false, the property cannot be deleted or edited (it cannot change any of its attribute).

You can use the Object.getOwnPropertyDescriptor() method to retrieve an object's own properties:

    let obj = { 
      age: 25 
    } 
    console.log(Object.getOwnPropertyDescriptor(obj, 'age')); 
    //{"value":25,"writable":true,"enumerable":true,"configurable":true} 

Meanwhile, the property can be defined using the Object.defineProperty() method:

    let obj...