Deno- JavaScript and TypeScript Runtime


Almost two years ago, Ryan Dahl, the creator of Node.js, talked about the ten things he regretted about Node.js. At the same time, he introduced DENO, a prototype of a new, security-first, npm-less JavaScript, and typescript runtime. Recently DENO 1.0 released.

Why Deno?

We know that javascript is the battle field-tested Dynamic language for the web, and we cannot imagine the web industry without JavaScript. Through standard organizations like ECMA international, the language has been evolving day by day. It’s easy to explain why is the natural choice for dynamic language tooling, whether in a browser environment or as standalone processes.

NodeJS: open-source, cross-platform, JavaScript runtime environment, invented by the same author almost ten years ago. People have found it useful for web development, tooling, creating a server, and many other use cases. In the presentation, ten things regret nodejs that are discussed in more detail.

Now the changing JavaScript world, and new additions like TypeScript, building Node projects can become a problematic effort, involving managing build systems and another heavy-handed tooling that takes away from the fun of dynamic language scripting. Furthermore, the mechanism for linking to external libraries is fundamentally centralized through the NPM repository, which is not in line with the web’s ideals.


Deno is a new runtime for executing JavaScript and TypeScript outside of the web browser. Deno attempts to provide a complete solution for quickly scripting complex functionality. [code]

Will it replace NodeJS?

NodeJs is a battle field-tested platform and incredibly well supported that is going to evolve day by day.

Typescript Support

Under the hood, deno built on V8, Rust, and Tokio. The rusty_v8 crate provides high-quality Rust bindings to V8's C++ API. So it is easy to explain written in particular TypeScript means we get a lot of the benefits of TypeScript even if we might choose to write our code in plain JavaScript. So deno does not require typescript compilation setup, deno do it for automatically.

#programming #javascript #node #code #deno

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Deno- JavaScript and TypeScript Runtime
Armando  Bruen

Armando Bruen


Meet Deno: The New JavaScript/TypeScript Runtime

Deno is Ryan Dahl’s (yeah, you guessed it right, the guy who created Node.js) latest venture.

But it isn’t just another JavaScript Engine. It also supports TypeScript — JavaScript’s strictly typed cousin — out of the box.

Installing Deno

On macOS, you can install Deno using Homebrew — the open-source software package manager for macOS:

brew install deno

Here’s a GIF to give you a better idea:

The output of the “brew install deno” command. Image Credits: Pratik Chaudhari (Author)

The output of the “brew install deno” command. Image Credits: Pratik Chaudhari (Author)

On Windows, Chocolately serves an alternative to macOS’s Homebrew:

choco install deno

On Linux, good ol’ curl will do the job:

curl -fsSL | sh

Once Deno is installed, one can run the following command to see all the command-line options that are available:

deno --help

The output of the above command will look something like below:

The output of executing the “deno” command on Terminal. Image Credits: Pratik Chaudhari (Author)

The output of executing the “deno” command on Terminal. Image Credits: Pratik Chaudhari (Author)

#deno #nodejs #typescript #runtime #javascript #programming

Rahul  Gandhi

Rahul Gandhi


Deno - A secure runtime for JavaScript and TypeScript

Pengenalan deno, dan membuat api sederhana dengan deno

00:06 Introduction Deno
01:49 Instalasi
03:52 Membuat Hello World
04:38 Membuat Server
07:50 Membuat REST API

#deno #node #javascript #typescript

Dylan  Iqbal

Dylan Iqbal


Deno, a Secure Runtime for JavaScript and TypeScript

Deno is a runtime for JavaScript and TypeScript that is based on the V8 JavaScript engine and the Rust programming language. It was created by Ryan Dahl, original creator of Node.js, and is focused on productivity.

#typescript #javascript #deno #developer #programming

Deno, a Secure Runtime for JavaScript and TypeScript

What is Deno?

Deno is a runtime for JavaScript and TypeScript that is based on the V8 JavaScript engine and the Rust programming language. It was created by Ryan Dahl, original creator of Node.js, and is focused on productivity. It was announced by Dahl in 2018 during his talk “10 Things I Regret About Node.js”

#deno #node #javascript #typescript #developer

Charles Cooper

Charles Cooper


Introduction to Deno: A Secure JavaScript & TypeScript Runtime

May 2020 saw the release of Deno 1.0, and it’s been a pretty popular topic of conversation. If you’re wondering what the fuss is all about, you’ve come to the right place!

In this article, I hope to give you an overview of what Deno is. We’ll take a look at its key features, and ask why you might want to start learning this new tool.

What is Deno?

So what is it Deno, and why was it created? It’s a JavaScript and TypeScript runtime, meaning you can write programs in either language and execute them from the command line. Unlike JavaScript run within a browser, Deno programs can access resources on the host computer, such as the filesystem and environment variables.

If you’re aware of Node.js, and you’re thinking that Deno sounds pretty similar, you’d be right. Deno is the brainchild of Node’s creator, Ryan Dahl, who created Deno to address what he sees as the design flaws in Node. The aims of the project are to provide a scripting environment that is secure by default, that treats TypeScript as a first-class language, and that is as browser-compatible as possible (where practical).

Security Features

Deno is designed to be secure out of the box. All code is executed in a secure sandbox by default, which means you need to give explicit permission to allow a program to access the network or the filesystem.

Programs can be granted permissions with the following command-line flags:

  • -A, –allow-all: allow all permissions (disables all security).
  • –allow-env: allow getting and setting of environment variables.
  • –allow-hrtime: allow high resolution time measurement (can be used in timing attacks and fingerprinting).
  • **–allow-net=**: allow network access. Optionally takes a comma-separated whitelist of domains.
  • –allow-plugin: allow loading plugins (unstable feature).
  • **–allow-read=**: allow file system read access. Optionally takes a comma-separated whitelist of directories or files.
  • –allow-run: allow running subprocesses.
  • **–allow-write=**: allow file system write access. Optionally takes a comma-separated whitelist of directories or files.

First-class TypeScript Support

As I mentioned earlier, Deno can execute both JavaScript and TypeScript. What’s more, it supports TypeScript as a first-class language. This means it can load and run your TypeScript code without any additional build step. There’s no need to set up additional tooling to transpile your code into JavaScript first.

Of course, since TypeScript is a superset of modern JavaScript, you can also write your code in good old JS if you want to! Deno supports some great, developer-friendly features such as ES Module imports

Using External Code

As Ryan mentioned in his talk, one of his goals for Deno was to avoid the need for a package manager. Unlike with runtimes/languages such as Node.js and PHP (which use the npm and composer package managers respectively), there’s no package manager for Deno.

Instead, external packages are imported directly via a URL:

import { Client } from "";

The first time you run your script, Deno will fetch, compile, and cache all the imports so that subsequent starts are lightning fast. Obviously there are times when you may want to force it to re-fetch the imports, and you can do this with the cache subcommand:

deno cache --reload my_module.ts

Package hosting

While Deno doesn’t provide a package registry as such, there’s a list of third-party modules available here. The service provides a standardized, versioned URL that maps to the module’s GitHub repo. You can search for packages by name and see a brief description, and click through to see the package readme.

The Standard Library

Deno provides a standard library — loosely based on Golang’s — which provides a set of high-quality standard modules with no external dependencies.

The packages in the standard library are not installed along with Deno. Rather, they’re available online and linked to as we saw in the previous section. The modules are versioned, allowing you to pin your code to the usage of a specific version:

import { copy } from "";

This means that any code you write that relies on a module from the standard library should continue to work in future versions.

The library includes various helpers and utilities you might need for building both command-line and HTTP-based applications:

  • archive: modules to work with tar files
  • async: async utilities
  • bytes: helpers for working with binary arrays
  • datetime: a helper for parsing date strings into Date objects
  • encoding: encoders for dealing with base32, binary, CSV, TOML, and YAML formats
  • flags: a command line arguments parser
  • fmt: a tool for printing formatted output
  • fs: helpers for working with the filesystem
  • hash: a module for creating hashes using a variety of algorithms
  • http: create HTTP and file servers, and manipulate cookies
  • io: utilities for string input/output
  • log: simple logging module
  • mime: provides support for multipart data
  • node: a (currently in-progress) compatibility layer for Node.js code
  • path: path manipulation utility
  • permissions: helpers to check and prompt for security permissions
  • signal: helpers for handling Deno process signals
  • testing: test assertions for using with Deno’s built-in test runner
  • uuid: utilities for generating and validating UUIDs
  • ws: helpers for creating WebSocket clients and servers

Installing Deno

Deno ships as a single executable with no dependencies. You can download a binary from the releases page, or install it using the installers below:

Shell (macOS, Linux):

curl -fsSL |  sh

PowerShell (Windows):

iwr -useb | iex

Homebrew (macOS):

brew install deno


Once installed, Deno can also upgrade itself to the latest release, using the following command:

deno upgrade

Or, you can up/downgrade to a specific version:

deno upgrade --version 1.0.1

The Future is Bright

The Deno manual suggests that it “is a great replacement for utility scripts that may have been historically written with Bash or Python”. While this is certainly true, I would expect to see it increasingly being used for the same use cases where Node.js is currently popular. There are already a number of Express/Koa-like frameworks cropping up, allowing you to build type-safe REST APIs, along with a growing number of third-party modules becoming available.

So, should you forget Node.js and start learning Deno? Current opinion in the industry is that Node.js is not about to disappear anytime soon, but Deno is definitely a technology to watch.

#deno #node #javascript #typescript #developer