Object-Oriented JavaScript - Second Edition

Object-Oriented JavaScript - Second Edition - Second Edition

Overview of this book

JavaScript is the behavior, the third pillar in today's paradigm that looks at web pages as something that consists of clearly distinguishable parts: content (HTML), presentation (CSS) and behavior (JavaScript). Using JavaScript, you can create not only web pages but also desktop widgets, browser and application extensions, and other pieces of software. It's a pretty good deal: you learn one language and then code all kinds of different applications. While there's one chapter specifically dedicated to the web browser environment including DOM, Events and AJAX tutorials, the rest is applicable to the other environments Many web developers have tried coding or adopting some bits of JavaScript, but it is time to "man up" and learn the language properly because it is the language of the browser and is, virtually, everywhere. This book starts from zero, not assuming any prior JavaScript programming knowledge and takes you through all the in-depth and exciting futures hidden behind the facade. Once listed in the "nice to have" sections of job postings, these days the knowledge of JavaScript is a deciding factor when it comes to hiring web developers. After reading this book you'll be prepared to ace your JavaScript job interview and even impress with some bits that the interviewer maybe didn't know. You should read this book if you want to be able to take your JavaScript skills to a new level of sophistication.

Object-Oriented JavaScript Second Edition

Credits

About the Authors

About the Reviewer

www.PacktPub.com

Preface

Free Chapter

Object-oriented JavaScript

A bit of history

ECMAScript 5

Object-oriented programming

OOP summary

Setting up your training environment

Summary

Primitive Data Types, Arrays, Loops, and Conditions

Strings

Primitive data types recap

Arrays

Conditions and loops

Code blocks

Switch

Loops

Summary

Functions

Summary

Objects

From arrays to objects

Built-in objects

Summary

Exercises

Prototype

The prototype property

Using the prototype's methods and properties

Augmenting built-in objects

Summary

Exercises

Inheritance

Prototype chaining

Inheriting the prototype only

Uber – access to the parent from a child object

Isolating the inheritance part into a function

Copying properties

Heads-up when copying by reference

Objects inherit from objects

Deep copy

object()

Using a mix of prototypal inheritance and copying properties

Multiple inheritance

Parasitic inheritance

Borrowing a constructor

Summary

Case study – drawing shapes

Exercises

The Browser Environment

Including JavaScript in an HTML page

BOM and DOM – an overview

BOM

DOM

Events

XMLHttpRequest

Summary

Exercises

Coding and Design Patterns

Coding patterns

Design patterns

Summary

Reserved Words

Keywords

Future reserved words

Previously reserved words

Built-in Functions

Built-in Objects

Object

Array

Function

Boolean

Number

String

Date

Math

RegExp

Error objects

JSON

Regular Expressions

Index

Customer Reviews

5 star

4 star

3 star

2 star

1 star

Math

Math is different from the other built-in objects because it cannot be used as a constructor to create objects. It's just a collection of static functions and constants. Some examples to illustrate the differences are as follows:

> typeof Date.prototype;
"object"
> typeof Math.prototype;
"undefined"
> typeof String;
"function"
> typeof Math;
"object"

Members of the Math object

Property/method	Description
`Math.E` `Math.LN10` `Math.LN2` `Math.LOG2E` `Math.LOG10E` `Math.PI` `Math.SQRT1_2` `Math.SQRT2`	These are some useful math constants, all read-only. Here are their values: > Math.E; 2.718281828459045 > Math.LN10; 2.302585092994046 > Math.LN2; 0.6931471805599453 > Math.LOG2E; 1.4426950408889634 > Math.LOG10E; 0.4342944819032518 > Math.PI; 3.141592653589793 > Math.SQRT1_2; 0.7071067811865476 > Math.SQRT2; 1.4142135623730951
`Math.acos(x)` `Math.asin(x)` `Math.atan(x)` `Math.atan2(y, x)` `Math.cos(x)` `Math.sin(x)` `Math.tan(x)`	Trigonometric functions
`Math.round(x)` `Math.floor(x)` `Math.ceil(x)`	`round()` gives you the nearest integer, `ceil()` rounds up, and `floor()` rounds down: > Math.round(5.5); 6 > Math.floor(5.5); 5 > Math.ceil(5.1); 6
`Math.max(num1, num2, num3, ...)` `Math.min(num1, num2, num3, ...)`	`max()` returns the largest and `min()` returns the smallest of the numbers passed to them as arguments. If at least one of the input parameters is `NaN`, the result is also `NaN`. > Math.max(4.5, 101, Math.PI); 101 > Math.min(4.5, 101, Math.PI); 3.141592653589793
`Math.abs(x)`	Absolute value. > Math.abs(-101); 101 > Math.abs(101); 101
`Math.exp(x)`	Exponential function: `Math.E` to the power of `x`. > Math.exp(1) === Math.E; true
`Math.log(x)`	Natural logarithm of `x`. > Math.log(10) === Math.LN10; true
`Math.sqrt(x)`	Square root of `x`. > Math.sqrt(9); 3 > Math.sqrt(2) === Math.SQRT2; true
`Math.pow(x, y)`	`x` to the power of `y`. > Math.pow(3, 2); 9
`Math.random()`	Random number between 0 and 1 (including 0). > Math.random(); 0.8279076443185321 For an random integer in a range, say between 10 and 100: > Math.round(Math.random() * 90 + 10); 79

Property/method

Description

Math.E

Math.LN10

Math.LN2

Math.LOG2E

Math.LOG10E

Math.PI

Math.SQRT1_2

Math.SQRT2

These are some useful math constants, all read-only. Here are their values:

> Math.E;
2.718281828459045
> Math.LN10;
2.302585092994046
> Math.LN2;
0.6931471805599453
> Math.LOG2E;
1.4426950408889634
> Math.LOG10E;
0.4342944819032518
> Math.PI;
3.141592653589793
> Math.SQRT1_2;
0.7071067811865476
> Math.SQRT2;
1.4142135623730951

Math.acos(x)

Math.asin(x)

Math.atan(x)

Math.atan2(y, x)

Math.cos(x)

Math.sin(x)

Math.tan(x)

Trigonometric functions

Math.round(x)

Math.floor(x)

Math.ceil(x)

round() gives you the nearest integer, ceil() rounds up, and floor() rounds down:

> Math.round(5.5);
6
> Math.floor(5.5);
5
> Math.ceil(5.1);
6

Math.max(num1, num2, num3, ...)

Math.min(num1, num2, num3, ...)

max() returns the largest and min() returns the smallest of the numbers passed to them as arguments. If at least one of the input parameters is NaN, the result is also NaN.

> Math.max(4.5, 101, Math.PI);
101
> Math.min(4.5, 101, Math.PI);
3.141592653589793

Math.abs(x)

Absolute value.

> Math.abs(-101);
101
> Math.abs(101);
101

Math.exp(x)

Exponential function: Math.E to the power of x.

> Math.exp(1) === Math.E;
true

Math.log(x)

Natural logarithm of x.

> Math.log(10) === Math.LN10;
true

Math.sqrt(x)

Square root of x.

> Math.sqrt(9);
3
> Math.sqrt(2) === Math.SQRT2;
true

Math.pow(x, y)

x to the power of y.

> Math.pow(3, 2);
9

Math.random()

Random number between 0 and 1 (including 0).

> Math.random();
0.8279076443185321
For an random integer in a range, say between 10 and 100:
> Math.round(Math.random() * 90 + 10);
79

Object-Oriented JavaScript - Second Edition - Second Edition

Object-Oriented JavaScript - Second Edition - Second Edition

Overview of this book

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Object-Oriented JavaScript - Second Edition - Second Edition

Math

Members of the Math object