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?
I think you may be missing the concept of ‘hydration’. A server side rendered app will deliver the pre rendered markup so that the client has something to immediately display while the framework continues to bootstrap in the background. It makes for much quicker and more efficient first loads, or ‘time to first paint’. A SSR website will still be a CSR website after hydration completes.
In addition, many web crawlers are unable to execute JavaScript. So for many single page applications, or CSR as you call them, they appear as a blank screen to less sophisticated crawlers because the content is never loaded. This is an catastrophe for things like SEO. SSR fixes this issue by delivering the content without regard to JS execution for the initial load.
If SEO matters beyond a couple landing pages, I find it unlikely that you would be developing a rich web app with that much reactivity. You are more likely content focused, in which case a static site generator or simpler SSR frameworks are easier and fit the use case much better. Even from a performance perspective, why ship the entire react run time if you do not need it?
And on the other hand, if you are developing a rich web app with a lot of interactivity, then do you really need SEO beyond a couple (or one) landing pages? You should develop the web app in React CSR and build the landing pages as static sites to optimize SEO. That is a lot easier to me.
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.
There are many scenarios you’d want seo and a csr. Let’s say you want a media player. Tons of interactivity, and lots of content. A landing page isn’t going to cut it.
But that’s the beauty of a framework like nuxt or next - you don’t have to choose. You can have your cake and eat it too so to speak.