What is Deno?

Deno is a JavaScript/TypeScript runtime with secure defaults and great developer experience. It’s built on V8, Rust, and Tokio. I suggest you watch these talks by Ryan: He talks about his mistakes with Nodejs here and a more in-depth look into deno here

Features

• Secure by default. No file, network, or environment access (unless explicitly enabled).
• Supports TypeScript out of the box.
• Ships a single executable (deno).
• Has built-in utilities like a dependency inspector (deno info) and a code formatter (deno fmt).
• Has a set of reviewed (audited) standard modules that are guaranteed to work with Deno. Scripts can be bundled into a single JavaScript file.

Lets Build Something!!!

In this article, we’re going to build a simple cli tool to demonstrate some of the features of deno. Our cli will be interacting with a COVID API to fetch live data.

Requirement: make sure you have deno installed. If you don’t, refer to this link. It’s pretty straightforward.

Deno has the entry file mod.ts so we will follow the same in this article if you are following this article along with the coding you can create a folder named covid-cli, inside that folder you can create a file called mod.ts and copy the below code there.

const { args } = Deno;
import { parse } from "https://deno.land/std/flags/mod.ts";

console.dir(parse(args));

Here the parse(args, options = {}); contains two parameters where args is an Array and options is an object, let try to run the above code using this cmd.

deno run mod.ts arg1 -f hello --flag World --booleanFlag

#deno #cli tool #tool