Book Image

Deno Web Development

By : Alexandre Portela dos Santos
Book Image

Deno Web Development

By: Alexandre Portela dos Santos

Overview of this book

Deno is a JavaScript and TypeScript runtime with secure defaults and a great developer experience. With Deno Web Development, you'll learn all about Deno's primitives, its principles, and how you can use them to build real-world applications. The book is divided into three main sections: an introduction to Deno, building an API from scratch, and testing and deploying a Deno application. The book starts by getting you up to speed with Deno's runtime and the reason why it was developed. You'll explore some of the concepts introduced by Node, why many of them transitioned into Deno, and why new features were introduced. After understanding Deno and why it was created, you will start to experiment with Deno, exploring the toolchain and writing simple scripts and CLI applications. As you progress to the second section, you will create a simple web application and then add more features to it. This application will evolve from a simple 'hello world' API to a web application connected to the database, with users, authentication, and a JavaScript client. In the third section, the book will take you through topics such as dependency management, configuration and testing, finishing with an application deployed in a cloud environment. By the end of this web development book, you will become comfortable with using Deno to create, maintain, and deploy secure and reliable web applications.
Table of Contents (15 chapters)
Section 1: Getting Familiar with Deno
Section 2: Building an Application
Section 3: Testing and Deploying

Conventions used

There are a number of text conventions used throughout this book.

Code in text: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "Add oak-middleware-jwt to the deps.ts file and export the jwtMiddleware function."

A block of code is set as follows:

const apiRouter = new Router({ prefix: "/api" })
apiRouter.use(async (_, next) => {
  console.log("Request was made to API Router");
  await next();

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

const app = new Application();
app.use(async (ctx, next) => {
  const start =;
  await next();
  const ms = - start;
  ctx.response.headers.set("X-Response-Time", `${ms}ms`);

Any command-line input or output is written as follows:

$ deno --version 
deno 1.7.5 (release, x86_64-apple-darwin) 
v8 9.0.123 
typescript 4.1.4

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "If you've used MongoDB, you can see your users created there on the Atlas interface, by going to the Collections menu."

Tips or important notes

Appear like this.