>A spotty connection hasn’t loaded the dependencies correctly - Either they load or they don't. How would the dependencies load "incorrectly"?

Let‘s say you have 5-7 dependencies to load, but 3 of them timed out because your train entered the tunnel. Your app ends up in incorrect state, fails silently and UX degrades unpredictably. This is where the conversion often drops visibly and the reason SSR is now a go-to solution for any marketing website.

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jazzypants 4 hours ago | parent [-]

Why am I loading dependencies from 5-7 places? Why is my website not using a bundler if it has so many varied dependencies? Why do we not expect the user to understand that they are in a tunnel without internet?

Regardless, this isn't really restricted to the usage of JavaScript. The website would likely have pretty bad UX if only half of the CSS loaded correctly, but no one programs defensively around it being absent.

	▲	ivan_gammel 2 hours ago \| parent [-]
		Have you ever developed an enterprise scale frontend applications optimized for conversion targets? It feels like you have not. You may ship your own code in a bundle, yes. All integrations come on top of that. That chatbot, tracker, A/B testing logic etc - all are loaded separately from your service provider CDN. An user opening a web page is not expecting a full-blown app with multi-second loading times. If that happens, they bounce, and you loose revenue. Web is supposed to have very short time to first content paint and very short time to interactive, the shorter, the better, less than 0.5s is the goal. It can deliver that, if built properly. Many SPAs, bulky JS apps are built this way for developer convenience, not for end users. The only real use case for SPA is when you deal with a lot of local data. A spreadsheet, document or image editor, a diagram tool (but then wasm is probably a better choice). You may say, you are not building enterprise grade frontend. But if you are small enough, you don’t need SPA either.