The Deno Show


In this episode of Syntax, Scott and Wes bring you the long-awaited Deno show — what it is, what it replaces, how you can use it, and more!

Deque - Sponsor

Deque’s free axe browser extension helps developers instantly catch 50% of accessibility bugs while they code. It’s lightweight, easy-to-use, and has zero false positives. Get started for free at

Sentry - Sponsor

If you want to know what’s happening with your errors, track them with Sentry. Sentry is open-source error tracking that helps developers monitor and fix crashes in real time. Cut your time on error resolution from five hours to five minutes. It works with any language and integrates with dozens of other services. Syntax listeners can get two months for free by visiting and using the coupon code “tastytreat”.

Mux - Sponsor

Mux Video is an API-first platform that makes it easy for any developer to build beautiful video. Powered by data and designed by video experts, your video will work perfectly on every device, every time. Mux Video handles storage, encoding, and delivery so you can focus on building your product. Live streaming is just as easy and Mux will scale with you as you grow, whether you’re serving a few dozen streams or a few million. Visit

Show Notes

02:13 - What is it?

  • A secure runtime for JavaScript and TypeScript
  • Built by Ryan Dhal — same guy who initially built Node.js
  • API is JS or TS out of the box

04:55 - Does it replace / what is it in relation to?

  • Node
    • It’s a replacement for Node.js
  • Express
    • Web Server Frameworks like Express will run on Deno, but Express itself won’t currently run because they are build on Node APIs
  • Serverless
  • React / Vue / Svelte
    • These things are just JavaScript, so they should/will work in Deno. Deno will replace your tooling. More involved things like Next.js that require Node APIs won’t work until.
  • SSR
    • It comes with all browser APIs out of the box!
  • Fetch
    • Window + Add Event listener
  • Webpack / Parcel / Snowpack
    • Deno is a bundler
  • Prettier
    • Deno is a formatter
  • TSC
    • Deno is a TypeScript compiler and runtime
  • ESLint
    • Deno is a linter
  • Jest
    • Deno is a Test Runner
  • NPM
    • Deno is a package manager - it pulls in packages from URLs

14:51 - Modules

  • ES modules from the start
  • Modules are loaded from URLs
  • Why? No package registry to worry about
  • This is how the browser works
  • Import from URL
  • You can also specify it in the json file
  • Fetch is built in!
    • It’s a browser API, but who cares?!
  • Browser APIs
    • window.add event Listener
    • Deno is event based, like the browser

20:10 - A nice standard library

22:14 - WASM

  • Deno can run WASM with the same APIs that the browsers can
  • Node is doing this too (experimental)

25:06 - Multi-threading with Web Workers

26:13 - Speed

29:44 - Security

33:39 - Run from anywhere

37:43 - Async out of the box

  • Everything is based on async + await / promises right away. No callback APIs, no promise wrapping.
  • Top level await

38:53 - Node Compatibility

  • Node APIs are being filled
  • This means if a browser package ships an ES module of a package, we can just import it

42:21 - What we’ve built

46:54 - Hosting

48:29 - Final thoughts

  • Scott: Now is a great time to learn, but don’t put any crucial work into that space unless you are ready to write everything. Libraries are still being written and evolved. Docs are still sparse. Many things didn’t work on first try. I had to read lots of source.
  • Wes: If You know JS or TS, you are already 90% there.
    • The package ecosystem isn’t there yet
    • Battle-tested
××× SIIIIICK ××× PIIIICKS ××× Shameless Plugs Tweet us your tasty treats!

Audio Player