Experimenting with Deno: A Secure Runtime for JavaScript and TypeScript published 9/16/2023 | 3 min read

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With the burgeoning advancement in JavaScript and the growth of its ecosystem over the years, Deno emerges as a secure runtime for JavaScript and TypeScript. Developed by Ryan Dahl - the mastermind behind Node.js, Deno is built to address quite a number of Node's criticisms. This blog post aims to delve deeper into Deno, touching on its benefits, key features, setup, and running a simple Deno application.

What is Deno?

Deno is a rustic, secure JavaScript, and TypeScript runtime built on V8, the same engine that powers Google Chrome and Node.js. Deno addresses problems in Node.js and provides a more modern and secure environment.

import { serve } from "https://deno.land/std@0.68.0/http/server.ts";
const server = serve({ port: 8000 });
console.log(`HTTP webserver running. Access it at:  http://localhost:8000/`);

for await (const request of server) {
  let bodyContent = "Hello Deno! 🦕";
  request.respond({ status: 200, body: bodyContent });

Why Deno?

  1. Secure environment: Unlike Node.js, which doesn't isolate the running script from the accessing file system, Deno is secure out of the box. It runs in a sandbox and needs explicit permission to perform actions like network access or altering the disk.

  2. ESModules: Deno supports ES modules as the default module system, and the modules can be imported directly from the URL.

  3. Built-in TypeScript support: Deno offers first-class TypeScript support with no configuration required.

  4. Standard library: Deno provides a comprehensive standard library that includes many useful functions, including datetime manipulation, hashing, testing, etc.

Setting up Deno

Installing Deno is easy and straightforward. For macOS users, you can install Deno with Homebrew.

brew install deno

Windows users can install Deno using Chocolatey.

choco install deno

Once installed, verify your installation by running:

deno --version

This should output the version of Deno installed on your machine.

Building a Simple Deno Application

Let's create a simple HTTP server using Deno.

Create a new file server.ts and add the following:

import { serve } from "https://deno.land/std@0.68.0/http/server.ts";

const server = serve({ port: 8000 });

console.log(`HTTP webserver running.  Access it at:  http://localhost:8000/`);

for await (const request of server) {
  request.respond({ status: 200, body: "Hello from Deno!" });

To run the application:

deno run --allow-net server.ts

Bear in mind that due to Deno's secure nature, we need to explicitly give the script network permission with the --allow-net flag.

Open your browser and navigate to http://localhost:8000/ to see your application running.


While Deno may not replace Node.js anytime soon, it provides a more secure and modern environment for JavaScript and TypeScript. It may be an excellent choice if you're looking for a lightweight, secure environment for your next project.

However, one point worth noting is that Deno is relatively new and lacks the vast, extensive community packages that Node.js offers. Before opting for Deno, consider package availability and compatibility to cater fully to your project's needs. Happy coding!

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