What Is Node.js? There are plenty of definitions to be found online. Let’s take a look at a couple of the more popular ones. This is what the project’s home page has to say:
Node.js is a JavaScript runtime built on Chrome’s V8 JavaScript engine.
And this is what Stack Overflow has to offer:
Node.js is an event-based, non-blocking, asynchronous I/O runtime that uses Google’s V8 JavaScript engine and libuv library.
Hmmm, “event-based”, “non-blocking”, “asynchronous I/O” — that’s quite a lot to digest in one go. So let’s approach this from a different angle and begin by focusing on the other detail that both descriptions mention — the V8 JavaScript engine.
Node Is Built on Google Chrome’s V8 JavaScript Engine The V8 engine is the open-source JavaScript engine that runs in Google Chrome and other Chromium-based web browsers, including Brave, Opera, and Vivaldi. It was designed with performance in mind and is responsible for compiling JavaScript directly to native machine code that your computer can execute.
However, when we say that Node is built on the V8 engine, we don’t mean that Node programs are executed in a browser. They aren’t. Rather, the creator of Node (Ryan Dahl) took the V8 engine and enhanced it with various features, such as a file system API, an HTTP library, and a number of operating system–related utility methods.
This means that Node.js is a program we can use to execute JavaScript on our computers. In other words, it’s a JavaScript runtime.
“Hello, World!” the Node.js Way You can check that Node is installed on your system by opening a terminal and typing node -v. If all has gone well, you should see something like v12.14.1 displayed. This is the current LTS version at the time of writing.
Node.js Has Excellent Support for Modern JavaScript As can be seen on this compatibility table, Node has excellent support for ECMAScript 2015 (ES6) and beyond. As you’re only targeting one runtime (a specific version of the V8 engine), this means that you can write your JavaScript using the latest and most modern syntax. It also means that you don’t generally have to worry about compatibility issues — as you would if you were writing JavaScript that would run in different browsers.