Node: Up and Running

First Steps in Code

This section will take you through a basic Node program before we move on to more in-depth programs.

Node REPL

One of the things that’s often hard to understand about Node.js is that, in addition to being a server, it’s also a runtime environment in the same way that Perl, Python, and Ruby are. So, even though we often refer to Node.js as “server-side JavaScript,” that doesn’t really accurately describe what Node.js does. One of the best ways to come to grips with Node.js is to use Node REPL (“Read-Evaluate-Print-Loop”), an interactive Node.js programming environment. It’s great for testing out and learning about Node.js. You can try out any of the snippets in this book using Node REPL. In addition, because Node is a wrapper around V8, Node REPL is an ideal place to easily try out JavaScript. However, when you want to run a Node program, you can use your favorite text editor, save it in a file, and simply run node filename.js. REPL is a great learning and exploration tool, but we don’t use it for production code.

Let’s launch Node REPL and try out a few bits of JavaScript to warm up (Example 1-6). Open up a console on your system. I’m using a Mac with a custom command prompt, so your system might look a little different, but the commands should be the same.

Example 1-6. Starting Node REPL and trying some JavaScript

$Enki:~ $ node
> 3 > 2 > 1
false
> true == 1
true
> true === 1
false

Note

The first line, which evaluates to false, is from http://wtfjs.com, a collection ...