React (and Vue, et al) was built with client side rendering in mind. It just does not seem to fit the server side rendering pattern.
What are the use cases? From my perspective, if your app is a rich web app with a lot of interactivity, you probably want CSR and don’t benefit much from SSR.
If you have a content-centric site, or a site with some interactivity but not much, you want a static site generator, or SSR. But in that case, a template engine with some smaller client side libraries (jQuery or AlpineJS or idk what all is out there).
Using React SSR for all of these seems like the wrong tool. What am I missing?
The biggest issue is flexibility. What if you don’t know if a page is going to need SEO or rich client side functionality when you build it, but then it does later? Do you want to rewrite the page from scratch every time that happens? This is especially true when you’re trying to maximize productivity for junior devs on a large team. Are all devs working on the site knowledgeable enough to make the static site vs CSR call correctly when they first start working on every new page? Wouldn’t a “Use framework X and we’ll figure that part out later” approach be easier for everyone?
Also, what about pages that need both SEO and rich client side functionality. You can choose to limit yourself to only one or the other on any given page, OR you could use hydration to have your cake and eat it too. Maybe react or vue isn’t the right abstraction, but if we can come up with a strong enough abstraction, hydration is a really useful general purpose pattern.
I suppose I just cannot imagine a situation where a rich interactive web app needs SEO that is not solved by having a separate landing page (and such solution not being way better and less effort than alternatives).
React has enough flexibility to be added later on to a project and not take over the entire web page, but only the parts it manages. It can act as a separate island or series of connected islands. So if you start thinking you dont need react but then later decide you want to add it to your non-react site, it should still be easily doable.