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: "If it says something similar to Command not found, double-check whether you've installed everything correctly, and verify that Node.js is in your $PATH environment variable."

A block of code is set as follows:

"babel": {
  "presets": [
    "es2017"
  ]
},
"main": "lib/main.js",
"scripts": {
  "start": "webpack-dev-server --inline",
},

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

$ brew install n
$ n lts

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: "We will mostly use the Elements and Console tabs, Elements to inspect the DOM and Console to play with JavaScript code and look for any problems."