I expect this post from Tim Kadlec to be quoted in every performance conference talk for the next few years. There is a lot of data here, so please check it out for yourself, but the short story is that JavaScript-framework-powered sites are definitely heavier and more resource-intensive than non-JavaScript-framework-powered sites. Angular is the beefiest and React is hardest on the CPU. But as Tim says:
… it says very little about the performance of the core frameworks in play and much more about the approach to development these frameworks may encourage
Another big caveat is that there isn’t data here on-site usage after first-load, which is a huge aspect of “single-page app” approaches.
Still, while you can be performant with frameworks (although even that top 10% isn’t super encouraging), the frameworks aren’t doing much to help what has turned into a bad situation. It mimics exactly what we talked about recently with accessibility. It’s not the frameworks “fault” exactly, but they are also the best positioned to stop the bleeding.
