Practical Deno: a practical guide to Deno

Introduction

The book "Practical Deno" (Fernando Doglio, 2021, 274 pp.) is a practical guide to building web applications in TypeScript using the Deno runtime. The author, an experienced developer and technical writer, aims to show Deno not just as a replacement for Node.js, but as a modern platform with improved security, built-in TypeScript support, and decentralized modules. The book is geared towards practitioners: each chapter contains ready-to-use code examples, exercises, and deployment tips.

What the book is about

"Practical Deno" covers the full cycle of developing a web application on Deno: from installation and environment setup to production deployment. Main topics:

• Installation and configuration — setting up Deno, working with TypeScript out of the box, configuration files.
• Module system — importing modules via URL, dependency management, working with npm packages through CDN.
• Security — Deno's permission model (--allow-read, --allow-net flags, etc.), code isolation.
• HTTP servers and routing — creating REST APIs using standard libraries and the Oak framework.
• Working with databases — connecting to PostgreSQL, MySQL, MongoDB via Deno drivers.
• Testing — built-in test runner, mocks, asynchronous tests, code coverage.
• Deployment — deploying to Deno Deploy, Heroku, Docker.

Who this book is for

The book is aimed at developers already familiar with JavaScript/TypeScript and with basic experience working with Node.js. It will be useful for:

• those who want to learn Deno from scratch and understand its advantages over Node.js;
• developers migrating existing projects from Node.js to Deno;
• professionals interested in modern runtime environments and TypeScript;
• students and teachers studying server-side development.

What the reader will learn

After reading the book, the reader will be able to:

• install and configure Deno, understand its architecture;
• use built-in TypeScript support without additional tools;
• work with modules via URL and connect external libraries;
• create secure web applications with access control to the file system and network;
• develop REST APIs using the Oak framework;
• connect and use databases (PostgreSQL, MongoDB);
• write and run tests, measure code coverage;
• deploy finished applications in the cloud (Deno Deploy) and containers.

Strengths of the book

• Practical focus — each section is accompanied by code that can be run immediately.
• Relevance — the book was published in 2021, when Deno was just gaining popularity, and still covers stable versions.
• Clear structure — from simple to complex, with gradual deepening into details.
• Special attention to security — the author thoroughly examines the permission model, which is rare in other guides.
• Comparison with Node.js — helps developers with Node.js experience understand Deno concepts faster.

Who it is recommended for

I recommend the book to anyone who wants to master Deno as an alternative to Node.js, especially if you value security, simplicity of configuration, and built-in TypeScript support. It will also be useful for teams considering migrating their server applications. Beginners in TypeScript may need prior familiarity with the language, but overall the book is written accessibly.