Book Image

Learning JavaScript Data Structures and Algorithms - Second Edition

By : Loiane Groner
Book Image

Learning JavaScript Data Structures and Algorithms - Second Edition

By: Loiane Groner

Overview of this book

This book begins by covering basics of the JavaScript language and introducing ECMAScript 7, before gradually moving on to the current implementations of ECMAScript 6. You will gain an in-depth knowledge of how hash tables and set data structure functions, as well as how trees and hash maps can be used to search files in a HD or represent a database. This book is an accessible route deeper into JavaScript. Graphs being one of the most complex data structures you’ll encounter, we’ll also give you a better understanding of why and how graphs are largely used in GPS navigation systems in social networks. Toward the end of the book, you’ll discover how all the theories presented by this book can be applied in real-world solutions while working on your own computer networks and Facebook searches.
Table of Contents (18 chapters)
Learning JavaScript Data Structures and Algorithms - Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface

Creating and initializing arrays


Declaring, creating, and initializing an array in JavaScript is as simple, as shown by the following:

var daysOfWeek = new Array(); //{1} 
var daysOfWeek = new Array(7); //{2} 
var daysOfWeek = new Array('Sunday', 'Monday', 'Tuesday', 'Wednes day', 'Thursday', 'Friday', 'Saturday'); //{3}

We can simply declare and instantiate a new array using the keyword new (line {1}). Also, using the keyword new, we can create a new array specifying the length of the array (line {2}). A third option would be passing the array elements directly to its constructor (line {3}).

However, using the new keyword is not best practice. If you want to create an array in JavaScript, we can assign empty brackets ([]), as in the following example:

var daysOfWeek = []; 

We can also initialize the array with some elements, as follows:

var daysOfWeek = ['Sunday', 'Monday', 'Tuesday', 'Wednesday',  'Thursday', 'Friday', 'Saturday'];

If we want to know how many elements are in the...