After almost two years, the wait is nearly over. The API has been frozen, and the countdown to Deno 1.0, officially scheduled for release on May 13, has begun.Due to its famous creator and forward-thinking vision, Deno is sure to be the most exciting and controversial JavaScript-related release in recent memory. Deno is a general-purpose JavaScript/TypeScript programming environment. It brings together many of the best open-source technologies and offers a comprehensive solution in one small executable file.Created by Ryan Dahl, best known as the mastermind behind&nbsp;<a href="https://blog.logrocket.com/node-js-12/" rel="noopener noreferrer" target="_blank" style="color: rgb(118, 74, 188);">Node.js</a>, Deno takes advantage of the JavaScript features that have been available since Node.js was released back in 2009. It also addresses the design flaws that Ryan talked about in his “<a href="https://www.youtube.com/watch?v=M3BM9TB-8yA" rel="noopener noreferrer" target="_blank" style="color: rgb(118, 74, 188);">10 Things I Regret About Node.js</a>” <iframe class="ql-video" frameborder="0" allowfullscreen="true" src="https://www.youtube.com/embed/M3BM9TB-8yA?showinfo=0"></iframe>lecture. Some are calling it the sequel to Node.js, although the author himself makes no such claim. Unlike Node.js, which was written in C++, Deno is written in Rust. It builds on top of the&nbsp;<a href="https://tokio.rs/" rel="noopener noreferrer" target="_blank" style="color: rgb(118, 74, 188);">Tokio</a>&nbsp;platform and, like Node.js, executes JavaScript using the V8 engine. One outstanding feature is that TypeScript is built in. While it still needs compiling into JavaScript to run, it’s done internally, so TypeScript behaves to the user as if it were natively supported.<h2> </h2>To download Deno, follow the instructions on the&nbsp;<a href="https://deno.land/" rel="noopener noreferrer" target="_blank" style="color: rgb(118, 74, 188);">homepage</a>. To update to future versions, use<pre class="ql-syntax" spellcheck="false">&nbsp;deno upgrade
</pre>To get help on any Deno subcommand, use either of the following.<ul><li>deno&nbsp;[subcommand]&nbsp;-h&nbsp;for a summary</li><li>deno&nbsp;[subcommand]&nbsp;--help&nbsp;for full details</li></ul>In this guide, we’ll cover all the killer features Deno 1.0 has to offer and provide examples of how to use them with the latest syntax. I’ll use TypeScript where possible, but the JavaScript equivalent should be obvious.I’m convinced that you’ll fall in love with Deno by the time we’re done. This guide should give you everything you need to get started.<h2> </h2>Deno is secure by default. By comparison, Node.js has full access to your file system and network. <h2>Deno is better?</h2>The experience in running my first Deno code snippet felt awesome. It took only a few steps;<ul><li>Install Deno (Tried in Windows using Powershell single command).</li><li>Copy-Paste the code snippet to a file.</li><li>Execute&nbsp;deno run &lt;filename&gt;The file can be either Typescript (.ts), or JavaScript(.js)</li></ul>I loved the fact that there isn’t any package.json file I had to create, defining the dependencies. All the dependencies were installed transparently by Deno, based on my URL imports in code, and the code just ran. Subsequent executions cached the dependencies unless I use the&nbsp;--reload&nbsp;flag.For a real-world project, Deno has a long way to go. Remember, we love Node, not only because of its programming language (JavaScript) and features but also due to the incredible community that built more than&nbsp;1 million&nbsp;libraries supporting the eco-system. So whether Deno will become better than Node, time will tell. <h2>Deno is fast?</h2>Deno is a runtime (not a programming language) that can execute JavaScript and TypeScript. Both Node and Deno use V8, Google JavaScript Engine for its execution. However, there are differences in their core implementation (Node uses C++ and Deno uses Rust), Event Loop &amp;, etc. These differences impact their performance. Besides, Deno needs to first compile TypeScript to JavaScript (happens transparently); it will increase the cold start time. Therefore, it’s essential to keep this in mind if you make any performance comparisons.So let’s come back to the actual performance comparison. When I look at the&nbsp;benchmarks&nbsp;available in Deno’s official site, I observed that the performance differences aren’t that significant. I feel we need more criteria before claiming that Deno is fast.So don’t expect any surprising performance gains by merely switching from Node to Deno, at least for the time being. <h2>Deno is lightweight?</h2>Deno easily stands out as a Single executable compared to Node. Having a single executable allows you to bundle Deno with applications easily and keeps the size footprint low. Deno fixes the node_modules bloat. You don’t get a package.json file or a mandatory node_modules folder within your project. These are some of the benefits of Deno’s dependency handling mechanism. The main advantage I have seen is that all the dependency handling mechanism that operates transparently to the developer. If the developer needs to get involved explicitly, he can do so (remember using--reload&nbsp;the flag we can ask to force install dependencies. Similarly, you can define the dependency folder). <h2>No more NPM or node_modules folder</h2>This one’s a biggy since everyone and their mother has had something to say about it in the past. Is it too bloated? Is it the wrong way to distribute dependencies? It is definitely one of the most controversial aspects of Node and Deno decided to get rid of it, altogether. So how is Deno handling dependencies? So far, by simply allowing you to require modules from anywhere. In other words, you can simply do:<pre class="ql-syntax" spellcheck="false">import * as log from "https://deno.land/std/log/mod.ts";
</pre>No need to have your own centralized repository anymore, but you do have to be careful with this practice, since importing modules from 3rd party sources you don’t have control over, leaves you open and exposed.In fact, our good pal&nbsp;package.json&nbsp;is also missing, dependency management is now simplified by having a list of modules and their respective URLs on a file called&nbsp;deps.ts&nbsp;. But what about versioning? I hear you ask. Well, you can specify the package version on the URL, it’s not really elegant, but it works.A normal&nbsp;deps.ts&nbsp;file could look like this:<pre class="ql-syntax" spellcheck="false">export { assert } from "https://deno.land/std@v0.39.0/testing/asserts.ts";
export { green, bold } from "https://deno.land/std@v0.39.0/fmt/colors.ts";
</pre>That will re-export modules and if you wanted to change their version, simplify modify the URL accordingly.The imported code is cached, by the way, the first time you execute the script and until you run it again with the&nbsp;--reload flag. <h2>So, will it replace Node.js anytime soon?</h2>Not really, to be honest, the title is a bit of a clickbait. Some of us started using Node.js back in the day when it was around version 0.10, and we were using it in production! It was a bit scary to tell you the truth, but we were doing it because there was nothing like it around. Neither PHP, Python or even Ruby (let alone Java or .NET) could compare to having JavaScript and an asynchronous I/O model in the back-end, all in one. And over all these years, Node (and JavaScript) has evolved to meet the industry’s requirements. Is it perfect? Heck no! But like anything else in life, there is no perfect when it comes to programming languages. Deno is no different, simply because right now, it’s just the culmination of around 2 years of work on an idea. It hasn’t been tried and tested in production systems yet. It hasn’t been reviewed and put into weird and unintended use cases to see how it deals with those border situations. And until it does, it’ll just be a toy for early adopters to play with. Maybe in a year, we’ll start hearing from companies sharing their experiences with it, how they’ve solved the newly found shortcomings, and eventually, the community behind it will adapt it to a point where it is useful. Will it replace Node then? Who knows! We’ll have to wait and see.

Deno:Intro

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