The guy who helped build React, the most popular workaround for the browser's layout engine, just said the workaround isn't sufficient and built the replacement himself.
Cheng Lou's resume is the context that makes this announcement hit different. He worked on React at Facebook. Created ReasonML and ReScript. Built Messenger's frontend. Now runs Midjourney's entire UI stack on Bun. Every single role was a fight against the same enemy: the browser's rendering pipeline.
Here's why this matters beyond the engineering flex. The web was built to render documents. Static HTML, flowing text, pages you scroll through. CSS layout was designed for that world. Then we started building applications inside the document renderer: spreadsheets, design tools, messaging apps, AI chat interfaces. Every one of those applications has to ask the browser permission to know how big text is. That question triggers reflow. Reflow locks the main thread. At 60fps you get 16 milliseconds per frame. Spend those milliseconds on layout recalculation and the user sees jank.
The industry's answer for the last decade has been to work around the problem. Virtual DOM (React) batches the writes. CSS containment limits the blast radius. content-visibility skips offscreen layout. FastDOM separates reads from writes. Every solution accepts that the browser owns text measurement and tries to call it less often.
Cheng Lou's answer: stop calling it at all. Measure text in pure TypeScript. Skip the DOM. Skip CSS. Skip reflow entirely. Zero layout passes. The performance improvement, per his demo, is categorical. 0.05ms versus 30ms. Zero reflows versus five hundred.
The person who understands the browser rendering pipeline better than almost anyone alive just built the tool that makes part of it unnecessary. That tells you where application-grade UI is heading.
My dear front-end developers (and anyone who’s interested in the future of interfaces):
I have crawled through depths of hell to bring you, for the foreseeable years, one of the more important foundational pieces of UI engineering (if not in implementation then certainly at least in concept):
Fast, accurate and comprehensive userland text measurement algorithm in pure TypeScript, usable for laying out entire web pages without CSS, bypassing DOM measurements and reflow