🚀 Getting Started with TypeScript in Deno

Vlad — Tue, 27 May 2025 09:49:44 +0000

If you're new to Deno, one of the best parts is that it supports TypeScript out of the box — no extra config, no bundlers, no headaches.

In this post, I'll walk you through why TypeScript is a game-changer and how Deno makes it easy to start using right away.

🧠 What is TypeScript?

TypeScript is a statically typed superset of JavaScript. It helps you write safer code by detecting bugs before your code runs. And best of all — with Deno, you don’t need a build step or tsconfig.json to get started.

✅ Why Deno + TypeScript is a Perfect Match

Native TypeScript support: Just use .ts files and Deno handles the rest
Cleaner project setup: No need for Babel, Webpack, or tsc
Improved tooling: Built-in formatter, linter, and test runner — all work with TS
Secure by default: Deno runs in a sandbox unless explicitly allowed

✨ Example: Hello TypeScript in Deno

// hello.ts
function greet(name: string): string {
  return `Hello, ${name}!`;
}

console.log(greet("Deno + TypeScript"));

Run it directly:

deno run hello.ts

Boom — TypeScript without any setup.

🔧 Need More Than Just One File?

Use Deno’s built-in module system:

// utils.ts
export function square(x: number): number {
  return x * x;
}

and import in another file

// main.ts
import { square } from "./utils.ts";

console.log(square(4)); // 16

🔍 What’s Next?

In the next posts, I’ll cover:

Organizing a Deno project with TypeScript
Using third-party modules with type definitions
Testing with Deno’s built-in test runner
Deploying TypeScript APIs with Deno Deploy

💡 Pro Tip: Deno’s built-in docs generator works great with TypeScript types. Try:

deno doc your_module.ts

Thanks for reading!
Follow me for more Deno + TypeScript tips.
Happy deno coding 🔧


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Let me know if you’d like a follow-up post — for example, setting up a REST API in Deno with full TypeScript types.