Introduction to Deno

Deno is a secure runtime for JavaScript and TypeScript that is built on V8, the same engine used by Google Chrome. It focuses on security, modern features, and a simple developer experience.

Key Takeaways:

• Secure by default with permissions for file, network, and environment access.
• Supports TypeScript out of the box.
• No package manager; uses ES modules and URLs for dependency management.

• Built-in TypeScript support.
• Secure by default; requires explicit permissions.
• Modern JavaScript features support.
• Efficient package management using URLs.
• Single executable file, no installation of separate packages required.

To install Deno, you can use the following command:

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

Alternatively, you can use Homebrew for macOS:

brew install deno

After installation, verify it by checking the version:

deno --version

Creating a simple HTTP server in Deno is straightforward. Here’s a basic example:

const http = Deno.listen({ port: 8000 });
console.log("HTTP server is running on http://localhost:8000");

for await (const request of http) {
  request.respond({ body: "Hello, World!\n" });
}
            

To run this example, save it to a file named server.ts and execute:

deno run --allow-net server.ts

This command allows network access, which is necessary for the server to listen for incoming requests.

When working with Deno, consider the following best practices:

• Use TypeScript for type safety and better tooling.
• Keep your code modular; utilize ES modules for dependencies.
• Manage permissions carefully; only allow what is necessary.
• Utilize Deno’s built-in testing framework for writing tests.