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: "The Triangle constructor takes three point objects and assigns them to this.points (its own collection of points)."

A block of code is set as follows:

    function sum(a, b) { 
    var c = a + b;
    return c;
    }

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

  mkdir babel_test
  cd babel_test && npm init
  npm install --save-dev babel-cli

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: "In order to bring up the console in Chrome or Safari, right-click anywhere on a page and select Inspect Element . The additional window that shows up is the Web Inspector feature. Select the Console tab, and you're ready to go".