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Object-Oriented JavaScript

Object-Oriented JavaScript

By : Antani, Stoyan Stefanov
4.5 (6)
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Object-Oriented JavaScript

Object-Oriented JavaScript

4.5 (6)
By: 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 (19 chapters)
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15
B. Built-in Functions
17
D. Regular Expressions

Chapter 2, Primitive Data Types, Arrays, Loops, and Conditions

Lets try and solve the following exercises:

Exercises

  1. The result will be as follows:
            > var a; typeof a; 
            "undefined" 
    

    When you declare a variable but do not initialize it with a value, it automatically gets the undefined value. You can also check:

            > a === undefined; 
            true 
    

    The value of v will be:

            > var s = '1s'; s++; 
            NaN 
    

    Adding 1 to the string '1s' returns the string '1s1', which is Not A Number, but the ++ operator should return a number; so it returns the special NaN number.

    The program is as follows:

            > !!"false"; 
            true 
    

    The tricky part of the question is that "false" is a string and all strings are true when cast to Booleans (except the empty string ""). If the question wasn't about the string "false" but the Boolean false instead, the double negation !! returns the same...

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