Modern Features in Deno

1. Introduction

Deno is a modern runtime for JavaScript and TypeScript that aims to provide a secure and efficient environment for running server-side applications. Created by Ryan Dahl, the original creator of Node.js, Deno addresses some of the shortcomings of Node.js and introduces several new features.

2. Key Features of Deno

2.1 Secure by Default

Deno runs in a secure sandbox by default, meaning it does not have access to the file system, network, or environment unless explicitly allowed.

Note: You can use flags like --allow-read and --allow-net to grant permissions.

2.2 TypeScript Support

Deno has built-in support for TypeScript, allowing developers to write applications with type safety without requiring additional tooling.

2.3 Single Executable

Deno is distributed as a single executable file, simplifying installation and deployment.

2.4 ES Modules

Deno uses ES modules for dependency management, eliminating the need for package managers like npm or yarn.

3. Using Deno

To get started with Deno, follow these steps:

Install Deno by running the following command:

curl -fsSL https://deno.land/x/install/install.sh | sh

Create a new Deno file, e.g., app.ts.
Write a simple server:

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

const s = serve({ port: 8000 });
console.log("http://localhost:8000/");

for await (const req of s) {
  req.respond({ body: "Hello World\n" });
}

Run your Deno application:

deno run --allow-net app.ts

4. Best Practices

Always use the latest version of Deno for improved features and security.
Organize your project using ES module imports for better maintainability.
Use Deno's built-in linter and formatter to keep your code clean.
Take advantage of Deno's testing framework for effective testing.

5. FAQ

What is Deno?

Deno is a modern runtime for JavaScript and TypeScript with a focus on security and developer experience.

How does Deno differ from Node.js?

Deno is designed to be secure by default, has built-in TypeScript support, and uses ES modules for dependency management.

Can I use NPM packages in Deno?

No, Deno does not use npm. You can import packages directly from URLs.