Deno is a secure runtime for JavaSript and TypeScript. It aims to replace Node.js which is the de-facto runtime when building modern JavaScript apps.
Deno was created by Ryan Dahl, who is also the creator of Node.js. According to Ryan in his famous conference speech, Node.js had few design flaws which became apparent as its usage exploded in the web development industry.
Some of the pain points of Node.js according to Ryan are
- Lack of Promises support in the initial design which led to non standard implementation to handle async code (untill the arrival of async/await).
- Security Issues by npm packages such as network access, file system access.
- Unnecessary complex wrappers to its build system GYP.
- Module system is poorly designed. Package.json and node_modules to manage dependencies is a well argued topic in the web development community.
He announced the alpha version of Deno on May 13, 2008. Today Deno is in stable release with version 1.1.x at the time of writing this post. Under the hood Deno is built with Rust upon Google’s V8 JavaScript runtime engine.
Some of the core features of Deno are
- All async actions return a promise in Deno which is drastically different from Node.js
- Improved Security. No file, network, or environment access, unless explicitly enabled.
- TypeScript support without additional tooling or configuration.
- Single executable file. No more npm, node_modules and package.json in the project.
- Dependency Inspector and Code Formatter are built in.
- Reviewed and Audited standard modules from deno.land/std or Deno Standard Library.
- Common Js
require()is replaced byimport fromES Module syntax
npm ecosystem and node_modules to manage dependency has become a huge pain for JavaScript developers. There were a lot of security issues due to unsecure packages. Basically Deno offers a new take on dependency management for the apps.
Deno Packages
Third Party Deno packages or modules are available via url https://deno.land/x
All the third party packages are imported via this url.
For example, Oak is a middleware framework for Deno which is similar to Express or Koa for Node.js
To import Oak, we simply use following line in our file
import { Application } from "https://deno.land/x/oak/mod.ts";
It is important to note that Deno downloads and caches all the imported modules. Cached modules will not be re-downloaded unless we specifically ask for it.
Hello World using Deno
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import { Application } from "https://deno.land/x/oak/mod.ts"; const app = new Application(); app.use((ctx) => { ctx.response.body = "Hello World!"; }); await app.listen({ port: 8000 }); |
Deno Tutorials on YouTube
I have collected a bunch of great high quality youtube tutorials to learn back-end development with Deno.
- Deno Crash Course by Brad Traversy
- Deno Course (6 Hour long) by freecodeCamp and The Codeholic
- Deno Crash Course by Web Dev Simplified
- Deno Jump Start Tutorial by Net Ninja
- Deno Websockets Tutorial by Net Ninja
- Practical Deno Projects by The Codeholic
Deno Tutorials on Udemy
Currently there is a full length Udemy Course by Andrie Neagoie. I hope there will more tutorials in the days to come.
Conclusion
Deno may become a serious contender to Node.js in the months to come. It has a long way to go before being used in production for serious web projects. It is an excellent and well designed JavaScript runtime environment. But Node.Js and npm ecosystem is not going away soon and may last for a decade or more.
Its good to have a basic understanding of Deno. This will be definitely a skill which may be demanded by employers once the ecosystem is mature enough to be used in production.
I hope to write more on Deno in the coming days and keep this list of tutorials updated. Thank you for reading and Have a great day !
