Node.js vs Deno

Node Js Vs Deno

 

Node.JS

The current LTS release of Node (v12.18.1 as of writing) supports modern JavaScript syntax and features. It also supports about 75% of the ES2020 spec. ECMAScript modules are also supported, but are currently only classed as experimental: you need to use the .mjs file extension, or add the property "type": "module" to your project’s package.json file.

In order to run TypeScript (or any other language) on Node, the code needs to be compiled to JavaScript that the V8 engine can execute. There are several different ways to do this, with different pros and cons, so getting up and running means having to choose one of these and follow the necessary setup process.

Deno

I was unable to find any mention of the JavaScript spec supported by Deno, but as it also uses V8 under the hood I would assume a similar level of support as in Node. My own tests show that Deno supports ES2020 features like Promise.allSettled() and the globalThis keyword. ECMAScript modules are the default, with CommonJS modules not supported unless you use the Node compatibility library (more about this later).

TypeScript is supported as a first-class language in Deno, meaning that it works out-of-the-box: no installing additional tools to transpile to JavaScript first. Of course, the V8 engine doesn’t support TypeScript natively, so Deno is still transpiling the code under the hood, but this is all seamless and transparent to you as a developer.