Data Structures and Algorithms with JavaScript

Chapter 1. The JavaScript Programming Environment and Model

This chapter describes the JavaScript programming environment and the programming constructs we’ll use in this book to define the various data structures and algorithms examined.

The JavaScript Environment

JavaScript has historically been a programming language that ran only inside a web browser. However, in the past few years, there has been the development of JavaScript programming environments that can be run from the desktop, or similarly, from a server. In this book we use one such environment: the JavaScript shell that is part of Mozilla’s comprehensive JavaScript environment known as SpiderMonkey.

To download the JavaScript shell, navigate to the Nightly Build web page. Scroll to the bottom of the page and pick the download that matches your computer system.

Once you’ve downloaded the program, you have two choices for using the shell. You can use it either in interactive mode or to interpret JavaScript programs stored in a file. To use the shell in interactive mode, type the command js at a command prompt. The shell prompt, js>, will appear and you are ready to start entering JavaScript expressions and statements.

The following is a typical interaction with the shell:

js> 1
1
js> 1+2
3
js> var num = 1;
js> num*124
124
js> for (var i = 1; i < 6; ++i) {
    print(i);
}
1
2
3
4
5
js>

You can enter arithmetic expressions and the shell will immediately evaluate them. You can write any legal JavaScript statement and the ...