If SPA is a thing why not many website migrating to it?

Why would a company that has a working platform go through the trouble of turning it into a SPA?

A few thoughts

1. It's a notable learning curve. New concepts such a stateless authentication and no sessions.
2. SEO. Google is getting better at trawling but concepts such as Isomorphic javascript are important
3. A lot of content to download client side can make the experience slower.

Good luck, it's the way forward in my opinion.

I agree with all of the above. And besides that, is it worth the investment? Do they get more sales out of it? Most of the big ecommerce sites are not build in a day, a week or a year. It is took years of building and fine tuning. Building it all over again takes a lot of time an thought and will cost a lot of money.

@GTHell I imagine it’s because, in my experience, every SPA I’ve used has been awful. They’re awful to navigate; use lots of memory because they have to download massive JavaScript bundles; have no regard for accessibility; and perform poorly in search engines. That’s not even beginning to think of the problems in developing them.

@CJJ Reddit is moving to React slowly over these months and now their platform is React only. I don't see why Amazon or other platform can't do the same.

@martinbean Why is everyone so hype with SPA like Vue or Reactjs? It take me 2-3x times to build something that can be done faster with static page but the benefit is also that I can build frontend functionality 5x times faster than static page with jQuery.

@GTHell They are simply a fashionable implementation of the design principle "separation of concerns" https://en.wikipedia.org/wiki/Separation_of_concerns

They are not a reason for Amazon and such to completely rewrite their domains as a matter of urgency. SEO would obviously be a huge concern for them. I would probably not use an SPA for an e-commerce domain, not just yet.

There are far easier and faster ways to build a website and they are not for the schoolboy developer. I work in a micro-service environment building internal solutions for a large company and having made the jump we have never looked back.

Why is everyone so hype with SPA like Vue or Reactjs?

everyone isn't. You're being hyperbolic. I think the fact that most aren't jumping on the latest spa fad should tell you something in and of itself, including the very good reasons laid out above.

@GTHell the only people who are "hyped" about SPA are people who don't care about user experience for anyone who isn't giving exclusive attention to their website when they have it open.

Just having any SPA website open severely impacts any browser's resource consumption, to the point where if I accidentally leave a SPA open in a tab for too long, my browser is probably going to halt, crash, or at least become extremely unresponsive until I find the offending tab and close it.

From the dev's perspective, SPA means less load on the server, more work done on the client. From a client's perspective, SPA means garbage.

Twaddle. SPAs are a natural evolutionary step. An integrated front-end is quicker and easier to build but by comparison SPAs are a contemporary lesson in best practice.

Isn't server side rendering there to solve that problem?