Cap'n Web: Cloudflare's Web RPC

News of the week of September 22, 2025: new default option in TS 6.0, Jiti upgrade, and Cloudflare's on a tear. Plus, npm's security roadmap. From the community: Python-style kwargs, running TS on MS-DOS, and running JS on PlayStation.

Chapters

• (00:00) - Welcome to the Show
• (07:42) - News: Take the State of JS Survey 2025
• (08:25) - News: TS 6.0 Will Enable noUncheckedSideEffectImports by Default
• (09:09) - News: Jiti 2.6 is Faster Thanks to RSPack
• (11:14) - News: ECMAScript Proposal for Non-extensibility Applying to Private Fields
• (13:06) - News: ECMAScript Proposal for Array.prototype.pushAll
• (15:00) - News: ECMAScript Proposal for Iterator Chunking
• (16:04) - News: Introducing Cap'n Web, a New RPC System for the Web
• (20:20) - News: Code Mode, Generating TypeScript Clients for MCP Servers
• (25:57) - News: Cloudflare Workers Have Improved Node Compatibility
• (28:24) - News: GitHub's Plan for a Secure NPM Supply Chain
• (33:22) - News: Astro 5.14 Adds Svelte Async Rendering and React 19 Actions
• (34:05) - Community Highlights: Scrimba's Free TS Course
• (34:28) - Community Highlight: Python-style kwargs in TypeScript
• (37:24) - Community Highlight: Porting TypeScript to Run on DOS
• (39:44) - Community Highlight: Running JavaScript on PlayStation
• (41:28) - Community Highlight: Is effect-ts Really Good, Or is it Just Hype?
• (44:19) - Cool Links: Tiny Helpers
• (45:17) - Cool Read: Itch Game Shout-outs
• (45:58) - Cool Tool: Autogenerate HTTPS Domains for Vite Dev Servers
• (47:23) - Cool Link: Find Out If You Have Unclaimed Money or Property
• (49:31) - The Minnesota Long Goodbye

News

• PSA: State of JavaScript 2025
• TS 6.0 will enable "noUncheckedSideEffectImports" by default 🎉 (h/t Rob Palmer)
• Jiti 2.6 – runtime for TS/ESM in Node.js is now using SWC/RSPack
• tc39/proposal-nonextensible-applies-to-private (h/t Rob Palmer)
  • “This breaking change means that if you seal/freeze an object, it cannot later have private fields stamped upon it ❄️”
• DanielRosenwasser/proposal-array-push-all (h/t Rob Palmer)
  • “It lets you append many items into an existing array without running out of stack memory 👍”
• tc39/proposal-iterator-chunking (h/t Rob Palmer)
  • “It lets you make iterators that can chunk & window content”
• Cloudflare: Cap'n Web: a new RPC system for browsers and web servers
• Cloudflare: Code Mode: the better way to use MCP
• Cloudflare: A year of improving Node.js compatibility in Cloudflare Workers (h/t James Snell)
• GitHub: Our plan for a more secure npm supply chain
• Metaframeworks: Astro 5.14

From the Community

• Course: Free TypeScript tutorial (Scrimba) 
• David Brownman: Python-style kwargs in TypeScript
• Jimbly: From Steam to Floppy: Porting Modern TypeScript to Run on DOS
• JSLegendWeb: You Can Now Make PS2 Games in JavaScript 
• Discussion: Is Effect-Ts really good or is it just hype? : r/typescript

Cool Stuff

• Cool Tools: https://tiny-helpers.dev/ (by Stefan Judis) 
• Cool Games: Minnesota-made games (by Martin Grider)
• Cool Game: https://andre-lima.itch.io/now-thats-a-big-dragon 
• Cool Game: https://mookie4242.itch.io/escape-the-well 
• Cool Tools: Caddy and Vite plugin (h/t nuqayah)
• PSA: Find Missing Money & Unclaimed Property (mn.gov / Go find your state)

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)