I'm guessing almost no one benefitted from cross-origin caching with React anyways, since it is almost always bundled up with Webpack. It's not like jQuery or Font Awesome.
Re:Etsy Moves from React to Preact
by eyelidlessness on Saturday February 05, 2022 @06:41PM
(#30227568)
I’m not sure I could quantify it, but CDNs were a prominent recommendation for React at least until CRA was pervasive.
Another thing worth mentioning, and another point in Preact’s favor, is ESM and tree-shaking. React still doesn’t officially ship ESM, and the ability to strip unused functionality at build time is hampered by that because ESM is more amenable to static analysis. Whereas Preact, which is already much smaller on the wire, can become smaller still because it supports ESM.
Not cross-origin, anymore. Every major browser now has cache partitioning (cache indexes are keyed by the requesting domain and the resource) for privacy reasons. Which means, for instance, the old optimization of using dependencies from a CDN is now suboptimal.