web-vitals

> Firstly, yes you can 20 year old paper. "Domain tagging," Felten and Schneider's proposed countermeasure, was implemented as "cache partitioning" in Firefox, Safari, and Chrome. If you're aware of extant issues please let me know. > In fact, I don't actually know of a time where I've seen perf metrics being used without tracking Google's own library: https://github.com/GoogleChrome/web-vitals#overview, which is recommended in OP's article. > I'm not in favour of that for something as trivial (in most case) as just making a website load slightly faster No performance RUM means no knowledge of performance regressions. I have deployed changes that looked great on our CI and then gravely impacted performance for a segment of customers. Blinding a business to user experience because you've read papers on historic exploits seems like odd log

I lead frontend development on a medium-sized US eCommerce shop for a few years. We prefetched JS bundles for likely page hits (e.g. grabbing category bundles when users land on the homepage). It improved performance a decent bit, though the far majority (>85%) of the site's users are on iOS, so RUM didn't show a big effect.* Hopefully the Safari team brings that to a stable release soon! *also why I dislike the focus from web.dev and family on CrUX. Fully 2 of the 4 Web Vitals are unmeasurable outside of Chromium[0], and CrUX only includes reporting from Chrome users anyway... I really wish they had delayed the SEO impacts of this stuff until there were usable analogs in competing browsers. That that caveat is not surfaced on Lighthouse/PSI reports does not make me happy either. [0]https://github.com/GoogleChrome/web-vitals#browser-supp

> to measure the Core Web Vitals you must use Chrome UX report No, you just need this bit of javascript: https://github.com/GoogleChrome/web-vitals

Thanks for the clarification, that makes sense. It is ironic that the vast majority of these performance issues are caused by render-blocking and CPU-sucking JavaScript, and so the recommended approach is to install yet another client side JS library (https://github.com/GoogleChrome/web-vitals/), which appears to only work in Chrome, and then use the library to post client side performance data to Google Analytics (though to be fair it could be any analytics). "How badly are all your JS libraries slowing down your page? Find out with this one weird JS library!" This seems like one of those things where if you get to the point where you need this, you're already in too deep.