The parts that absolutely require JS can't be reliably linked to and nobody indexes that stuff. Most apparent SPA:s serve a HTML alternative if you don't claim to be a web browser in the UA.
Cloudflare and the like are also fairly easy to deal with as long as your crawler is well behaved. You can register the fingerprint and mostly get access to cf:ed websites.
The parts that absolutely require JS can't be reliably linked to and nobody indexes that stuff. Most apparent SPA:s serve a HTML alternative if you don't claim to be a web browser in the UA.
Cloudflare and the like are also fairly easy to deal with as long as your crawler is well behaved. You can register the fingerprint and mostly get access to cf:ed websites.