Introducing Valleys: A Lightweight TypeScript Validation Library

News of the week of August 18, 2025: one of the biggest nightly updates for TS Go, Rspack team announces a new linter, the new minor Bun release is pretty major, and Next.js 15.5 features typed routing . From the community: more learning web dev resources, an exhaustive switch utility for JSX, --strict on by default?, and whether you can really protect your code from clients. Plus, the two fools rant about feature flags.

Chapters

• (00:00) - Welcome to the Show
• (06:32) - News: TypeScript Go Got a Big Nightly Update
• (10:01) - News: Rspack Introduces Rslint
• (13:08) - News: Bun 1.2.21 Got Some Major Upgrades
• (18:10) - News: Deno 2.4.4 Improves Structured Clone Performance
• (19:21) - News: Next.js 15.5 Features Type-safe Routing
• (20:55) - News: Preact 11 Beta is Even Faster with Better Hydration
• (21:27) - News: Angular 20.2 Goes Zoneless
• (23:25) - Community Highlight: Dr. Axel's Learning Web Dev Series
• (25:08) - Community Highlight: A Hopeful PR to Enable --strict By Default
• (26:38) - Library Watch: valleys, Lightweight Runtime Data Validation
• (28:05) - Community Highlight: Hangman Written in TypeScript Types
• (28:59) - Community Highlight: Exhaustive Switch Expressions by Replo
• (31:42) - Discussion: How to Protect Code and Assets in the Browser
• (36:59) - Cool Game: Now THAT'S a Big Dragon!
• (38:05) - Cool Read: Auto-tiling with the Dual Tile Map Technique
• (38:33) - Cool Tip: Using IIFEs for Scratch Variables to Avoid Allocations
• (40:43) - Cool Vid: A Million Blades of Grass Written in LOVR and TypeScript
• (42:31) - The Minnesota Long Goodbye

• Jake Bailey: TSGO had a big nightly update
• Socket.dev: Rspack Introduces Rslint, a TypeScript-First Linter Written in Go (powered by TS Go) (repo)
• Bun 1.2.21 release notes plus blog post on how they achieved a 500x faster postMessage(string)
• Deno 2.4.4 structured clone perf improvement 
• Next.js 15.5 release notes (summary thread)
• Preact 11 sneaks in a beta
• Angular 20.2.0 features a stable zoneless API 

From the Community

• Dr. Axel: 
  • Learning web development: Booleans, comparisons and `if` statements
  • Learning web development: Loops in JavaScript
  • Learning web development: Shells and Node.js
• Daniel Rosenwasser proposed to turn `--strict` on by default 
  • Correction: It was an issue, not a PR :-)
• Lib watch: valleys (ht HN) –  Lightweight, zero-dependency library for validating arbitrary runtime data in TypeScript.
• Hangman in TypeScript types
• Discussion: Protect code & assets? : r/typescript
• Replo.computer: Exhaustive Switch Expressions in Typescript

Cool Stuff

• Blog post: Dual Tilemap Auto Tiling 
• Steam Game: Now THAT’S a Big Dragon
• Video: A million blades of grass in LOVR + TypeScript
  • LÖVR - VR version of LOVE 2D
  • TypeScriptToLua
• Join the Michigan TS Discord!

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)