Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "Using the isEmpty method, we can simply verify whether the length of the internal array is 0."

A block of code is set as follows:

function Stack() { 
  //properties and methods go here 
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

class Stack { 
 constructor () {
 this.items = []; //{1}
 } 
  push(element){ 
    this.items.push(element); 
  } 
  //other methods 
}

Any command-line input or output is written as follows:

stack.push(5);
stack.push(8);

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "When you open Firebug (simply click on its icon), you will see the Console tab, and you will be able to write all your JavaScript code in its command-line area."