Deno is a JavaScript & TypeScript runtime built on V8 -- the same JavaScript engine used by the Google Chrome browser. The origins of Deno are rooted in Node JS, which is another JavaScript runtime that's also built on the V8 JavaScript engine.

If the need to build something on top of a perfectly good JavaScript engine used by a mass-market browser like Google Chorme confuses you, let's break down this need:

Therefore, Deno is an improved amalgamation of JavaScript features and concepts, facilitating tasks that were once difficult to achieve in modern JavaScript development. That said, if you landed here without any prior knowledge about what led up to Deno, I'd recommend you first read the Node JS tutorial and TypeScript tutorial.

Deno - Installation

Because Deno is still relatively new, there's only one major version 1.x.x at the time of this writing vs. Node JS versioning which has fifteen major versions.

Note Deno uses a parallel versioning scheme for its standard modules, currently at a sub-1.0 version (e.g. 0.95). Loosely speaking, this shouldn't matter since the Deno intended for wide use and the topic of this tutorial -- dubbed Deno CLI -- is the only version that matters for end users, not to mention a given Deno CLI version is always pegged and compatible against a given Deno standard module version as described in this mapping list.

When it comes to installation, Deno is available for many operating systems either via an installation script or through a package manager[2], in addition to being available in source code so it can also be built to run on any platform.

In most cases, a few mouse clicks or command line instructions will be sufficient to install Deno. For example, executing curl -fsSL | sh is enough to install the latest Deno version on your operating system.

Once you successfully install Deno, it will provide a deno exeuctable that's typically installed on a user's home directory under the .deno folder inside the bin sub-directory (e.g. for a user called admin, the Deno executable will be in /home/admin/.deno/bin/).