// the find
swyxio/async-render-toolbox
BECAUSE PERFORMANCE SHOULD BE SEXY
A Chrome/Firefox extension from 2018 that injects a lag radar (LagRadar) into any page to visualize React async rendering jank. Built as a demo tool to complement Dan Abramov's React Suspense talks at the time. It's a curiosity piece, not a production debugging tool.
The core idea is sound — a visual frame-rate indicator overlaid on any page is genuinely useful for spotting render-blocking work. The permission model is honest: no auto-injection, only runs when you click the button. It's a thin, focused extension with no build toolchain required — just raw extension files you can read in two minutes.
Abandoned in April 2018 — React's async rendering story changed completely after this was written and it was never updated to track any of it. The Chrome Web Store link is almost certainly dead or pointing at an outdated version. Zero tests, zero CI, no package.json — 'very rough right now' was accurate then and nothing changed. The Firefox compatibility issue listed as future work was never resolved.