TypeScript.fm - The Friendly Show for TypeScript Developers

This week Kamran and Erik unpack JSR, the new open alternative to the npm registry from the folks at Deno. They both published packages and discuss what JSR offers npm doesn't, when to use it, and how it works for both consumers and maintainers.

• (00:00) - The Sheer Joy of Publishing to JSR | Ep 6

• TypeScript 5.8 RC Released -- Notably, the checked return expressions was walked back 🥹 But, it includes require(esm) support.
• Deno announced the JSR Open Governance Board
• Warn or emit lint errors if your TypeScript contains erasable syntax with Josh Goldberg's new ESLint plugin
• Windows Terminal 1.22 released with support for Sixels graphics
• Node 20 got require(esm) support backported.
• PSA: Node 18 EOL is April 30, 2025
• React team officially deprecates Create React App
• Browser vendors met to discuss which APIs to implement between them at Interop 2025
• Prettier 3.5 released with better TS support
• Astro 5.3 has better overall performance and Netlify support

Community Highlights

• Tutorial: FreeCodeCamp build a React and TypeScript Wheel of Names project
• Video: Repository pattern and clean architecture with TypeScript / Prism (h/t Alex Rusin)
• Blog post: The Sheer Joy of Publishing to JSR (h/t  I. Welsch Canavan)
• Blog post: Deno on npm: specifiers vs transpiled services like esm.sh
• Via The Good Dr. Axel Rauschmayer
  • Blog Post: extracting parts of composite types via `infer`
  • Blog Post: A guide to tsconfig.json (Updated for TS 5.8)
  • Blog Post: TypeDoc: testing code examples in comment docs
  • Blog Post: Mapped Types
• Discussion: dayjay migrated all their Node.js projects to Deno. What did they learn?
• Tools: Nir Tamir created a TS ESLint rule for sorting object properties by type
• Tools: Kevin Deng is working on Unloader & Unplugin
• Tools: A new Deno Bundler (dsbundle)

 Deep Dive: JSR

• JSR, an open source npm alternative
• JSR's Provenance Attestation for verification
• Zero-config GitHub publishing
• Doesn't yet support private publish (but there's a workaround)
• No support in Artifactory yet
• JSR will warn you of slow types
• Kamran published ts-has-guards for guarding `Map.has` and related APIs
• Erik published Excalibur's ECS core code for fun
• JSR will score your package
• No scope squatting (or selling)!

Secrets of the Handbook

• Decorators
• 2ality's guide on decorators
• TC39 updates presentation
• oxc is working on support for modern and legacy

Links

• Kat

This week Kamran and Erik try to dissect the complex landscape of JavaScript and TypeScript compilers, transpilers, interpreters, engines, and runtimes (oh my!). What are the tools, what are they used for, why is the world so complicated, and what should you care about as a TS developer?

• (04:55) - This Week in TypeScript: Node.js Corepack Issue Affects Users

• 📌 PSA: Node.js LTS corepack registry key signing issue breaks people's CI/CD pipelines and npm/pnpm installations. If you are affected, check this issue out! It’s fixed now and backported to Node 20.18.3.
• 📌 PSA: There was a remote code execution vulnerability in Vitest, and a Vite dev server vulnerability. Update to the latest patch versions!

Community Highlights

• Blog Post: TypeScript enums: use cases and alternatives (Axel Rauschmayer)
• Blog Post: Tutorial: publishing ESM-based npm packages with TypeScript  (Axel Rauschmayer)
• Blog Post: Move on to ESM-only (Anthony Fu)
• Blog Post: Fetch and HTTP/2 support in Node.js, Bun and Deno (George Haidar)
• Learning: Nx is doing cool stuff for TS monorepo setups and has a whole series on it
• Cheatsheet: Bookmark this TypeScript Cheat Sheet by Zero to Mastery (PDF version available)
• Book: Joshua Goldberg has a new Learning TypeScript book and shares a tip about TS comments

 Compilers and Runtimes Deep Dive

• The JavaScript Runtime Environment (Jamie Uttariello)
• Wikipedia: ECMAScript Engines
• V8's interpreter, Ignition
• Hermes engine for React Native
• TSC, the official Microsoft TypeScript compiler
• SWC, a Rust-based compiler for JavaScript and TypeScript
• esbuild, a Go-based compiler for JavaScript and TypeScript
• oxc, a (new) Rust-based compiler by the creators of Vite
• Deno compile for creating binary executables
• Bun runtime, a drop-in replacement for Node
• workerd runtime by Cloudflare
• Vercel Edge Runtime
• A list of WebAssembly (WASM) runtimes
• WinterTC, a committee for unifying server backend runtime APIs

Links

• TypeScript 4.0's labeled tuple elements (playground link)
• Wondering what version of Node supports what ES features and syntax? https://node.green/
• Replace those ugly TS errors in VSCode with something more pretty

Sponsored by Excalibur.js
Excalibur.js is the friendly TypeScript game engine for making 2D web games. Use your TypeScript or JavaScript skills to make games! Excalibur comes out-of-the-box with everything you need to make web games, like physics, sprites, animations, sound effects, input, and particles. Design your assets with tools like Aseprite and Tiled, then load them natively using first-party plugins.

Music
Seahorse Dreams by Kubbi (Spotify)

Creators & Guests

This week Erik and Kamran talk about Vite (Vight? Veet?), what it's good for, how it works, and its status as the "go-to" tool for frontend tooling.

• (04:21) - This Week in TypeScript: TS 5.8 Beta

• News: TS 5.8 Beta Released
• News: Ruck 9, a Deno web framework
• News: Guy Bedford releases [email protected], allowing type stripping in the browser
• Community: Qwik and Deno (📸 Video)
• Community: Benchmarking Zig, TS and WASM by David Bushell (✍️ Blog Post)
• New Libraries
  • tsc-extra
    • Static analysis tool, type checking only, no code generation or compiling
    • Useful for documentation or lower-level TS tools
  • Typemap is like a Zod alternative, built for TypeBox
    • “It offers a common TypeScript syntax for type construction, a runtime compiler for high-performance validation and type translation from one library to another.”

 Vite Deep Dive

• Homepage
• Evan You's State of Vite 2023 Keynote (📸 Video)
• Why Use Vite?
• Vite 6 Updates
• Sapphi-Red's Increasing Vite's Potential With the Environment API (✍️ Blog Post)
• Vite's browser compatibility
• Vite's future, bundling with Rolldown

Links

• Handbook: Type Guards and Predicates
• Send typesafe emails with React.email
• Better string literal errors (📸 Video)

Sponsored by Excalibur.js
Excalibur.js is the friendly TypeScript game engine for making 2D web games. Use your TypeScript or JavaScript skills to make games! Excalibur comes out-of-the-box with everything you need to make web games, like physics, sprites, animations, sound effects, input, and particles. Design your assets with tools like Aseprite and Tiled, then load them natively using first-party plugins.

Music
Seahorse Dreams by Kubbi (Spotify)

Creators & Guests

This week Erik and Kamran make poor dad jokes, talk about Deno, and tour its ecosystem. If you're new to Deno, this will be a great introduction!

• (00:00) - We Don't Talk About Deno-no-no-no | Ep 3

• Bun 1.2 released
• Matt Pocock's take on erasableSyntaxOnly
  • TC39 Types as Comments proposal
• Tailwind 4 released
• Vitest 3 released

Deno Deep Dive

• Deno’s 2024 in review blog post
• Rusty v8 -- Rust bindings for V8
• Deno CLI docs
• Performance
  • Deno benchmark stats
  • Denosaurs benchmarks
  • AWS Lambda cold-starts
• Deno Fresh
• JSR
• Deno Deploy
• Kamran's Advent of Code 2024 repo using Deno

Links

• Learn Vim’s keyboard shortcuts with Vim Adventures
• Minnesota's Art Shanty Projects during the winter
• Secrets of the Handbook: TSConfig – extendedDiagnostics
• Alias to serve a folder using a single Deno command like npx serve (h/t Kamran)
• Deno Compile video with Flappy Bird

Sponsored by Excalibur.js
Excalibur.js is the friendly TypeScript game engine for making 2D web games. Use your TypeScript or JavaScript skills to make games! Excalibur comes out-of-the-box with everything you need to make web games, like physics, sprites, animations, sound effects, input, and particles. Design your assets with tools like Aseprite and Tiled, then load them natively using first-party plugins.

Music
Seahorse Dreams by Kubbi (Spotify)

Creators & Guests

In this episode, Kamran and Erik discuss the newly released TypeScript support with Node 23.6 and its implications. What's supported? What's not supported? And how does it differ from Bun or Deno?

• (00:00) - Ep 2 - Node 23 Gets TypeScript Support

• Everything You Need to Know About Node.js Type Stripping by Marco Ippolito
  • Node 23.6.0 Release Notes -- The one with TypeScript support
  • Docs: Node 23 “Modules: TypeScript”
  • Node's new built-in support for TypeScript by Dr. Axel Rauschmayer
• Native Typescript support coming to Eleventy by Zach Leatherman (PR)
• ESLint 9.18 – Zero-config TypeScript support by Andrey Sitnik
• TypeScript 5.8: Erasable Syntax Only
• PSA: Create React App doesn’t work with React 19, use Vite!

Errata

• 19:11 -- We incorrectly assumed that TSC is used for the transpilation in Node 23, but that's not true. SWC still handles the transpilation (if the flag is used) so Node's TypeScript support does not rely on TSC at all. Reported by: Marco Ippolito

Cool Stuff

• Jiti: A Node.js package for ESM and TypeScript support
• Example of `satisfies never` with switch statements by Cecile Muller, Bluesky
  • What is the “satisfies” type constraint? By Matt Pocock
• Dockview – npm package for a TypeScript native window manager
• Using “as const” for config typing by Matt Pocock

Sponsored by Excalibur.js
Excalibur.js is the friendly TypeScript game engine for making 2D web games. Use your TypeScript or JavaScript skills to make games! Excalibur comes out-of-the-box with everything you need to make web games, like physics, sprites, animations, sound effects, input, and particles. Design your assets with tools like Aseprite and Tiled, then load them natively using first-party plugins.

Music
Seahorse Dreams by Kubbi (Spotify)

Creators & Guests

In the inaugural episode of TypeScript.fm, the two fools introduce themselves, share their "origin stories," and share plans for the podcast. Briefly covered in the news: Vite 6, Deno 2's expansion of the ecosystem, Node 23's new TypeScript support, and the latest Excalibur.js 0.30.0 release.

• (00:00) - Ep 1 - Two TypeScript Fools, One Podcast

• Vite 6 is out! Check out the new Environments API.
• Deno 2.1 was released in November -- Node.js compatibility, npm packages, WebAssembly
• Node 23 support for TypeScript (via Matt Pocock)
• Excalibur.js v0.30.0 - Performance improvements, GPU particle acceleration, brand new Excalibird tutorial, and more

Links

• StackOverflow 2024 Survey – TypeScript is #5 in Programming Languages
• Zod - TypeScript-first schema validation
• QuickJS -- Embeddable JavaScript engine (like Lua for C)
• Nivo -- Charting library with TypeScript support

Sponsored by Excalibur.js
Excalibur.js is the friendly TypeScript game engine for making 2D web games. Use your TypeScript or JavaScript skills to make games! Excalibur comes out-of-the-box with everything you need to make web games, like physics, sprites, animations, sound effects, input, and particles. Design your assets with tools like Aseprite and Tiled, then load them natively using first-party plugins.

Music
Seahorse Dreams by Kubbi (Spotify)

Creators & Guests