Lynn Beighley - Jumpstarting JavaScript

Copyright 2017 Lynn Beighley. All rights reserved.

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December 2017: First Edition

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2017-12-13 First Release

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J avaScript is a programming language that web browsers can run. Browsers like Firefox and Chrome are built with engines that can understand and execute programs written in the JavaScript language. Firefox has an engine called SpiderMonkey, and Chromes engine is called V8.

Running JavaScript in a browser limits what you can do with it. For example, with JavaScript in a browser, you are limited to interacting with web pages. You can detect errors when people enter information in a form. You can open browser windows and alert boxes. But you cant control anything outside of a browser.

Fortunately, you have another option. When you install and use the JavaScript extension Node.js, your JavaScript code can run independently of a web browser. (Youll often see Node.js simply called Node, and thats what well do for the rest of this book.)

Node is the V8 JavaScript engine bundled together with libraries that handle input/output and networking. This means that Node lets you use JavaScript outside of a browser to run shell scripts, manage back-end services, and run directly on devices.

What You Bring to the Book

• Basic familiarity with programming concepts
• Ability to set up and connect a Raspberry Pi
• Ability to access and use a console
• Understanding of sudo, directories, and file creation/editing

Chapter 1
Meet JavaScript and Node.js!

T his chapter takes you through the steps to install Node on your Mac, Windows, or Linux OS. Then youll check to see that its working.

As you install Node, you may notice that something called npm is also being installed. This program is the Node Package Manager.

Node is really popular, and it has a whole new ecosystem of useful Node-based code packages other developers have created for you to use. When you want to use one of these packages in Node, you need an easy way to install and manage them. Thats what npm does for youit installs additional Node packages you want to use.

Follow the instructions for your system then jump to the last section, Node Is Installed Now What?

Although you could build Node from the source code, this guide is all about getting you going quickly. The easy way is to visit the official Node website, Nodejs.org, and use an automated installer. Here are the steps involved:

Step 1. Visit ).

Nodejs.org download page

Step 2. Find the file you downloaded and double-click it. Youll see the installation dialog (). Click Continue to go through the installation. Stick with the default settings.

Step 3. When the installation finishes, youll see a summary screen with installation information ().

Node installer