Book Image

Object-Oriented JavaScript - Third Edition

By : Ved Antani, Stoyan STEFANOV
5 (1)
Book Image

Object-Oriented JavaScript - Third Edition

5 (1)
By: Ved Antani, Stoyan STEFANOV

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 (25 chapters)
Object-Oriented JavaScript - Third Edition
About the Authors
About the Reviewer
Customer Feedback
Built-in Functions
Regular Expressions

Iterators and iterables

ES6 introduces a new mechanism of iterating over data. Traversing a list of data and doing something with it is a very common operation. ES6 enhances the iteration constructs. There are two primary concepts involved with this change-iterators and iterables.


A JavaScript iterator is an object that exposes the next() method. This method returns the next item from the collection in the form of an object that has two properties-done and value. In the following example, we will return an iterator from an array by exposing the next() method:

    //Take an array and return an iterator 
    function iter(array){ 
      var nextId= 0; 
      return { 
        next: function() { 
          if(nextId < array.length) { 
            return {value: array[nextId++], done: false}; 
          } else { 
            return {done: true}; 
    var it = iter(['Hello', 'Iterators...