Comment by com2kid
4 years ago
> And most of them don't spend the time to implement HTML5 history properly, so they break the URLs - which means you can't bookmark or deep link into them and they break the back/forward buttons.
The majority of routers for React, and other SPA frameworks, do this out of the box. This has been a solved problem for half a decade at least. A website has to go out of its way to mess this up.
That aside,
SPAs are great for a number of reasons:
1. You aren't mixing state across server and client. Single Source of Truth is a thing for a good reason. If you have a stateful backend, and your front end naturally has the state of whatever the user has input, you now have to work to keep those two in sync.
2. You need a beefier backend. A SPA backed by REST APIs is super easy to scale. nginx can serve up static resources (the JS bundle of the site) LOLWTF fast, and stateless REST apis are easy peasy to scale up to whatever load you want. Now you just have to worry about backend DB, which you have to worry about with non SPAs anyway.
3. Less languages to deal with. If you are making a modern site you likely have JS on the front end, so with SPA you have JS + HTML. With another backend framework you now have JS+HTML+(Ruby|Python|PHP|C#|...), and that back end code now needs to generate HTML+JS. That is just all around more work.
I agree some sites shouldn't be a SPA, a site that is mostly text content consumption, please no. A blog doesn't need to be a SPA. Many forums, such as HN, don't need to be a SPA.
But if a site is behaving like an actual application, just delivered through a web browser, then SPAs make a ton of sense.
Your arguments seem to be assuming a particularly bad implementation of a traditional backend.
1. A good server-generated-HTML backend will have no more state than a good server-generated-JSON backend. The client state is all stored in the client either way, whether in JS variables, HTML tags, or the URL.
2. A good server-generated-HTML backend doesn't do significantly more work just because its output is in HTML instead of JSON. A bit of extra text generated isn't going to increase your CPU load in any meaningful way.
3. There are only fewer languages to deal with if you aren't in charge of writing backend code. If you're in charge of the backend code, you still have to pick a backend language for your JSON API.
I think you're assuming that the choice is "SPA" or "messy stateful monstrosity". It's perfectly possible to build a RESTful HTML-based API that is as clean and stateless as any JSON API. PHP's been starting each request with a clean slate for decades.
Your arguments seem to be assuming a particularly bad implementation of a traditional backend.
Whenever someone says "this particular architecture is bad!" they're talking about a bad implementation of it.
The point is whether or not you're more likely to succeed at making a good app with an SPA or a multi-page site. For pretty much all brochure-styles websites and many SaaS webapps you're more likely to achieve success (for every common understanding of success) by using a multi-page architecture because they're usually simpler to implement, they work the way browsers expect things to work, and you don't need to implement some hard things yourself. You can make a brilliant SPA website for any purpose, but often people try and fail. Saying "you shouldn't have used an SPA" is shorthand for "You didn't understand or implement an SPA well enough, and now your web thing is failing to serve users as well as it should, and using a multi-page architecture would have avoided the problems your website has now."
> Your arguments seem to be assuming a particularly bad implementation of a traditional backend.
These weekly SPA complaint threads always assume a particularly bad implementation of a SPA as well though.
You always have to fight with incompetency in any large codebase.
Incompetency exists the most in whatever the first thing that coders learn is.
I'm old enough to remember when that was c++, then it was java, php, ruby, jquery, now it's react.
It's always a trade-off. You can build things in the "cheapest" language (whatever the first one currently is) but then you'll inevitably get the cheapest code
That's really what this conversation is about in the long arc of coding
Skills and people are a pyramid. The more competency you demand the harder the people are to find.
We have this tendency to taint the tool by the users.
Incidentally after a language or tool loses "first learned" status it generally slowly regains its prestige.
We don't assume a c++ shop is a bunch of morons any more or that using php means you write nothing but garbage. One day vue/react/whatever will lose its first language status as well and I'll be here reading about something that might not have been invented yet being a trashy bad no good idea
Ultimately the technical merits are mostly cover for a conjecture of economic efficiency. There's a reason why people aren't defending things like applications built with Go/wasm bridges - those people are expensive
The key here is that if we consider equivalent good and robust implementations, equivalent capable teams, same UX, etc of an SPA and a traditional full stack MVC application with a modern ajax tool such as livewire, hotwire, etc the latter takes a fraction of the time and cost to build and the result is far less complex and easier to maintain.
I've worked in both kinds of environments, and unless you're building an offline first app, dogma, or Google maps...SPAs make absolutely no sense from the engineering point of view.
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Multi-page forms without some front end stuff ends up with the very clunky either "rerender previous form pages over and over again, except hidden", or "have some token to track partial form data", or "build up a DB to store a partially complete form".
With some frontend work you can have a multi-page form just work, with the data stored in the client up until final submission, and only sending in partial checks ahead of time. This is qualitatively easier to handle, in my opinion.
It also seems extremely uncontroversial that sending data for a single item is going to require less text generation than sending over that data + the entire page.
These are all gradients, but people make absolute claims that don't hold up in these arguments.
"It also seems extremely uncontroversial that sending data for a single item is going to require less text generation than sending over that data + the entire page."
And yet... so many SPAs feel so much slower than MPAs. They suck down MBs of JavaScript, constantly poll for more JSON and consume crazy amounts of CPU any time they need to update the page.
If you're on an expensive laptop you may not notice, but most of the world sees the internet through a cheap, CPU and bandwidth constrained Android phone. And SPAs on those are just miserable.
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I see your point, but managing state is not free on the client side either. Frontend frameworks usually come with some built in state management, but once it starts to be more complicated we often need to find a 3rd party library to manage it.
I agree that there are many cases where managing the state in the frontend is the preferred solution. Multi-page forms add complexity for both frontend and backend. Sometimes frontend is less complex, and other times the backend is simpler.
I'll add some comments on your statements regarding backend. I'm not saying it is a better solution than managing it on the frontend for all cases. My point is that although it adds complexity on the backend, it does not necessarily mean that managing state on the frontend is simpler. That depends on the use case, but I think a lot of developers "default" to handling state on the frontend that adds much more complexity than a simple backend solution.
> "rerender previous form pages over and over again, except hidden"
In that case, you would only render hidden <input> fields with the values, and not the complete form. The code for receiving "step x" of the flow, would simply read the parameters from the request and include the values in the html code.
> "have some token to track partial form data"
Using <input> fields for this is much simpler. The final page would just read all variables as if they where posted from the same form, without requiring to generate/parse any tokens
> "build up a DB to store a partially complete form"
Most frameworks have a built in "session" that abstracts this away. It may be stored in a database, file, memory etc. If you require distributed sessions, the framework often handles this transparently by just configuring the session manager to use something like Redis to store the data.
> "rerender previous form pages over and over again, except hidden"
There are modern ways to do this, see Unpoly, HTMX, livewire, hotwire, etc. You're comparing with an outdated view of what an MVC application looks like. It's like to complain about SPAs because of backbone.js
> "have some token to track partial form data"
This is called "sessions", the token you refer to can be a cookie, which is done by default for free on any MVC framework. Doing this in any other way lead to either losing authentication on page reload or security vulnerabilities (storing a token in localstorage, etc).
> "build up a DB to store a partially complete form"
Again, you can store partial data in a session, for free. As it comes by default with any MVC framework.
One of the key points here is that with any of the popular MVC frameworks you don't need to rebuild the wheel and the car from scratch as with SPA frameworks, most of these things come for free, specially anything related to forms. This is something we're not used to have in the SPA world and everyone has a different way to deal with it.
> Multi-page forms without some front end stuff
Nobody says there shouldn't be any frontend stuff, you still need it of course. If fields are static between steps you can just render every step and toggle between different set of fields using something like Alpine, no need to reload from the server. If fields are dynamic and need some kind of database lookup between steps, Unpoly or livewire/hotwire make this trivial.
Please, let's stop comparing Next.js/React top modern SPAs to 20 year's ago struts MVC, it has not been like that since many years ago already.
I've built a multi-page form in an SSR app with a tiny dash of JavaScript. The form's children are divs. The Next button hides the current div and shows the next one. The final Submit button is just a regular submit.
If you get into more than 3 pages, this isn't a great approach for various reasons, but you don't need to reach for a framework the instant you have a multi-page form.
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The alternative to SPAs is not 90s pages reloads.
Nowadays you have livewire, hotwire, unpoly, htmx and several other modern solutions.
Most SaaS developers aren't serving APIs to their clients, they are serving websites and web applications.
Applications have state. In order to render and deliver the application, the server needs to have some concept of what that state is.
> a bit of extra text
Doesn't really sound like an application, but a website.
In a web app it can happen that you use it for an hour without the backend doing a single thing.
> There are only fewer languages to deal with if you aren't in charge of writing backend code.
You don't have to deal with them at the same time
> Doesn't really sound like an application, but a website.
"text" here is as in "text/html", not as in "English-language copy".
> In a web app it can happen that you use it for an hour without the backend doing a single thing.
I would submit that this is an extremely rare case. The most involved web apps I interact with (say, Figma) are constantly syncing their state with the server. The simplest (say, TurboTax) save state as I move on to the next screen.
If you do have a case where you can pull that off, then by all means use an SPA. But it's weird to say that something isn't a web app unless it can go long periods of time without server interaction.
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> Doesn't really sound like an application, but a website.
That's probably the key thing - most companies building SPA's don't really need an application but a website. There are many interesting products that need to be applications because of the functionality they need, but for every one such product there's at least a dozen that does not.
> Doesn't really sound like an application, but a website.
Yeah, well, from the name of it, doesn't that sound like what the Web is for?
I mean, we already have systems to run applications on; they're called operating systems.
Not only SPAs but "web applications" as a whole are a mistake IMO.
There is no black or white here. 98% of every site is in between those things and you could consider them one way or the other. Is reddit a website or an application? is a backoffice dashboar a website or an application?.
The problem with SPAs is not the technology or the architecture itself. The problem is everyone thinks, by your own definitions, they are building an "app" by default.
I've already worked for several teams which struggle to get almost anything done and everything takes ages to ship because of the fanaticism of using React for everything. God, some didn't even know you could submit a form without building a json API endpoint.
> isn't going to increase your CPU load in any meaningful way.
yes but it would be soul crushing for a developer
Why?
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> 1. You aren't mixing state across server and client. Single Source of Truth is a thing for a good reason. If you have a stateful backend, and your front end naturally has the state of whatever the user has input, you now have to work to keep those two in sync.
If this were true, you wouldn't need a REST API. I don't understand what you're trying to say here. When you make a REST call to get data, you instantly have two different sets of state: the client and the server. It's no different from SSR, it's just transmitted in a different data format (json vs html).
> 2. You need a beefier backend. A SPA backed by REST APIs is super easy to scale. nginx can serve up static resources (the JS bundle of the site) LOLWTF fast, and stateless REST apis are easy peasy to scale up to whatever load you want. Now you just have to worry about backend DB, which you have to worry about with non SPAs anyway.
You do the exact same thing with SSR. Stateless shared nothing app tier instances. Been doing it for 15 years now.
> 3. Less languages to deal with. If you are making a modern site you likely have JS on the front end, so with SPA you have JS + HTML. With another backend framework you now have JS+HTML+(Ruby|Python|PHP|C#|...), and that back end code now needs to generate HTML+JS. That is just all around more work.
You can use JS on both the frontend and backend. Or ClojureScript. Or TypeScript. I'm sure there's others. But yes, for many languages this is a potential negative of SSR.
> If this were true, you wouldn't need a REST API. I don't understand what you're trying to say here. When you make a REST call to get data, you instantly have two different sets of state: the client and the server. It's no different from SSR, it's just transmitted in a different data format (json vs html).
SSR means you don't have a clear representation of the client-side state (as distinct from the presentation) - by definition you render on the server and only serve the view layer to the client, whereas your data model only lives on the server. There will naturally be state in the client (e.g. form inputs), but you don't have a good representation of that in your model.
> You do the exact same thing with SSR. Stateless shared nothing app tier instances. Been doing it for 15 years now.
OK so where does the UI state live - not the long-term persistent entities, but things like unvalidated form input, which tab is enabled, which step of an in-progress wizard the user is on? Either you manage that on the client (at which point you're halfway to an SPA, and getting the worst of both worlds), or you manage it in the application layer on the server (in which case you have all the scaling issues), or you make every UI change go all the way into the data layer which has even bigger performance issues.
That state lives on the context of the page. That's the point of having a URL/page lifecycle that reloads the context.
If you need to persist past a reload then a few lines can save to localstorage. Anything more requires server-side calls anyway.
This magical state that can only be managed on the client-side with a heavy SPA is a myth for 99.9% of sites.
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Regarding a rest call (#1) being out of sync ... usually the "state" is in the database... if you're using SSR, it's still a separate context of state than what may be in the database a fraction of a second later.. and if you wish to keep that in sync, you're still going to need JS, or some other goofy hacks to do so.
> You aren't mixing state across server and client. Single Source of Truth is a thing for a good reason. If you have a stateful backend, and your front end naturally has the state of whatever the user has input, you now have to work to keep those two in sync.
This is a bit weird to me, in that I'd say that cuts in the opposite direction. State can exist in at least three locations for most applications: db, app server, and client. Keeping state consistent across all of them can be difficult in the best of times, but thin clients by their very nature carry less state, lessening the burden. Sometimes client state is necessary, for richer user interactions, but for all but the most cosmetic of purposes you're going to have to replicate that state on the backend anyway, to enforce business and security requirements.
> but for all but the most cosmetic of purposes you're going to have to replicate that state on the backend anyway, to enforce business and security requirements.
This really just comes down to what you're writing, how app-like your web app is. It's too easy to have one's own experience focused in a certain area and estimate the remaining majority as relatively similar. (For most of what I personally work on, the DB portion is mostly a simple straightforward serialization of what the user has built through the application; whereas client-side state has so many aspects to it I couldn't give a brief characterization—the whole app is basically client-side.)
From what I can tell most of the disagreement about SPAs results from devs who are building things that aren't app-like railing against their futility vs devs who are, who become perplexed by the vitriol when they have immediate experience with their architectural benefits.
> From what I can tell most of the disagreement about SPAs results from devs who are building things that aren't app-like railing against their futility vs devs who are, who become perplexed by the vitriol when they have immediate experience with their architectural benefits.
The SPA criticics from the article and this thread have repeatedly said that their issue is not with building things that need the benefits an SPA architecture brings. The criticism is that the majority of SPAs are harmed by that architecture because it is the industry default and being used when it isn't appropriate.
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This is missing the real reason that people write SPAs, which is that React solved web components, which are hugely beneficial for almost 100% of web sites, and thus became the standard for building web sites, and with React it's easier to make an "SPA" than to make a "traditional" site and users don't know or care either way.
Users care they just don’t know why many modern websites are bad websites. Every website is now an app whether that actually makes it better UX or not.
Web components actually aren't that good. Most seasoned and experienced developers I know hugely prefer either ASP.NET webforms or one of the many Java MVC implementations. We all know and use React daily, but I've literally seen the same application built faster with better maintainability and scalability once it was moved away from a SPA.
Also the React programming model is brilliant.
Anyway the point is that people write SPA's because of React, not the other way around.
Wicket has offered a beautiful component approach for over a decade now. Having seen it I can't stand page-oriented MVC frameworks (indeed it's good enough that it convinced me that OO actually has some merit in some cases).
I used Wicket quite extensively about 10 years ago so my comments may not be true anymore. I began using Wicket as it was so much better than Struts and JSF. However, the development of new custom widgets in Wicket was so much more convoluted than implementing the same widget in Backbone.js. And it was hard to inject new functionality into and existing page. I eventually refactored all my UI code into jquery+ backbone.js ( this was before React ) and that code is in production and still working. And the new developers maintaining it don't see any reason to refactor that into React or Vue.
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Is this the Wicket you're referring to? https://wicket.apache.org/
What's the best intro you know to how it's components work, and the benefits and tradeoffs over other approaches?
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I agree with all your points, but I think it's worth pointing out that those benefits you mentioned are largely for the developers. As a consumer I love a well-written SPA when the problem set calls for it, but most of the SPAs I have to use are garbage. I don't fault the tech for that, although I suspect that a lot of those SPAs were created by "me too" people that just wanted to build a SPA. When React was in the pre 1.0 days, I did that, and several people on my team as well (so I'm not casting any stones here, just trying to state facts).
Last time I bootstrapped a React SPA I don't think cra includes a router ootb.
> but most of the SPAs I have to use are garbage
As an example, look at reddit. I'm still using old.reddit.com because I can't stand their fancy SPA UI. It is so bad to the point, as a user, I enjoy a lot more HN's interface than reddit's one.
2. Hard to believe that is true in the general case.
Typical scenario for SPA is to use some sort of REST API, these API:s are usually designed for general usage, not specific usage, i.e. designed to be reused between components and views thus they basically return everything of a specific model regardless if data is needed or not.
Therefore the controller queries the database with the equivalent of SELECT * on a table (or perhaps multiple tables with joins) and then exposes every field.
And in many cases one request is not enough because the common generic design of REST APIs, thus a few request more are fired that results in multiple SELECT * against the database, and eventually the equivalent of SQL JOIN is performed in JavaScript.
Already SPA solution has an increased cost by asking for data that is currently not needed, not only in the traffic between the database and the backend but also in the traffic between the backend and the frontend.
And because we want to be good REST citizens we sprinkle the JSON payload with timestamps, resource urls and pagination information and what not and in majority of cases never to be used.
Comparing that to SSR where you can fetch what you need from the database with custom SQL query (I hope you do, otherwise the SQL leprechaun will make a visit).
Just imaging how much data there is on the web that is requested and then just discarded, not even looked at.
It is possible to design custom REST endpoints for each component, but then of course what is the point of a SPA then? If you are already writing a custom REST endpoint just return HTML instead of JSON and then swap in the new and swap out the old for your component (one-liner), the end result is the same.
SQL -> (Array of) object(s) -> JSON -> Javascript (Array of) object(s) -> HTML
can therefore be shortened to
SQL -> (Array of) object(s) -> HTML
3. That doesn't make any sense, number of languages are still the same regardless.
GraphQL is such a quality of life upgrade coming from this environment, especially at the scale where your frontend teams are potentially larger and shipping more than the teams closer to the SQL can provide.
GraphQL is a consequence of the SPA design, a bad design leads to a worse fix.
The drawback is that the frontend now has its own schema, often it starts as a naive direct mapping of the real schema.
Thus any changes in the real schema also need to change the frontend schema and every use of it, or the mapping to the frontend schema needs to change.
Eventually these two schemas will diverge because it is not feasible that every schema change results in frontend change. Especially if the idea is to have two different teams working from either side, then the backend team can’t wait for the frontend team therefore the schema mapping will change.
And the thing is that the frontend shouldn’t be aware of how the backend schema is constructed, if the User model is separated into three different tables, because of some technical reason, that should not change how the frontend operates. The frontend understanding of what a User is shouldn’t be the same as the backends.
Therefore ideally frontend schema and the backend schema will always differ. They don’t view the world the same way.
However what you now have is a slow mapper between the frontend schema and backend schema.
The point of relationship databases is that you can view your data from different perspective by doing different SQL queries. That is already built in. But now we have invented yet another layer on top of SQL, usually in combination with the already monstrosity called ORM.
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GraphQL is just another artificial solution to a problem created by SPAs themselves. Same as SSR, hydration, server components, client side routers, dynamic bundles loading, dynamic translations loading, etc, etc, etc. A whole industry of workarounds for a broken idea. Now 10 years after SPAs became popular we starting to approach a point were we almost have what we already had.
What I really don't get is why we don't just expose SQL directly at this point. Is it just security? Database servers have fairly extensive authentication and authorization models.
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> The majority of routers for React, and other SPA frameworks, do this out of the box. This has been a solved problem for half a decade at least. A website has to go out of its way to mess this up.
They might not mess up history when using a standard routing library, but I've seen plenty of devs forget to add unique titles to different pages which is frustrating for a user with multiple tabs going.
On SO the accepted answer for react-router looks like "create a custom Page component with title as a prop"[0]. At work I just ask folks to use react-helmet.
[0] https://stackoverflow.com/questions/52447828/is-there-a-way-...
> . You aren't mixing state across server and client. Single Source of Truth is a thing for a good reason. If you have a stateful backend, and your front end naturally has the state of whatever the user has input, you now have to work to keep those two in sync.
Why would I want to keep any state on the client? What in the history of the web (the whole idea being its someone elses computer) would make it a good idea to take away the one major selling point of the web? That no matter what, someone else has the state I need, and I never have to worry about losing that if something happens to my connection. It either went through or it didn't.
> The majority of routers for React, and other SPA frameworks, do this out of the box. This has been a solved problem for half a decade at least. A website has to go out of its way to mess this up.
99% of SPAs break history related features in some way.
97% of statistics cited on HN are made up on the spot.
99% of people don't FRICKING care.
Most of the users I have to deal with still have problems with double clicking.
They don't understand basic browser features.
They don't understand that they can set preferred language in their browser.
History related features are not an argument in any way.
They do care. It also ensures end users are endlessly frustrated by inconsistent UI / UX handling.
They do care if the experience doesn't work right, even if they don't understand why.
Why would people not care that browsing URLs work well?
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"A website has to go out of its way to mess this up."
I know it's supposed to be easier, but I keep seeing teams mess this up.
I can say I've seen a lot of state management issues with SPAs... more with Angular than React, and almost none when using React+Redux well.
I think a part of this is that a lot of developers simply don't desire, want to, get to or otherwise take the time to understand the framework they are using... It has been true forever... I can't tell you how many times I've seen stuff copy/pasted from StackOverflow, by devs that don't understand what they're doing, or they add jQuery to a React application, and have goofy interactions.
The lack of understanding will always be a thing, you have to learn, most learn by doing, and when starting out, you don't know that what you are doing isn't good, but it kind-of works.
React+redux well is a huge if.
Last time I used redux, about 4 years ago, every tutorial on it demonstrated a completely different way of using it.
I spent a week piping a couple dozen form inputs through redux.
Throw typescript in there and life got more complex.
Maybe it sucks less now. But I've seen plenty of websites where every key press causes crap tons of state to get copied around because "lol const only". I've seen sites where typing takes a second per character due to mis use of redux, and the problem with redux is that it is easier to misuse than to use properly.
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Tried ngrx?
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I just don't know how it could be made any easier to not mess up. You really truly do need to go out of your way to mess it up, or be entirely unfamiliar with the JavaScript routing framework or library you're using.
They do, but it's usually the anti-SPA people who mess it up, by refusing to work with the grain of their tools. It's not quite the same thing as "strategic incompetence" but it feels related.
Client-side routing for page-oriented stuff is certainly not a solved problem: the basics, sure, but not actually doing it properly. There are some parts of the experience that it’s not possible to do perfectly because the web doesn’t expose the necessary primitives, and exceptionally few things go beyond the basics of just clobbering and resetting scroll position on back/forward. To do it properly, you need to restore all transient UI state (form field contents/state, scroll positions, focus, selection, media playback position; zoom level, probably not implementable; and there may be more, though I don’t include things like <details open> as transient state since that’s put into the DOM) on back/forwards, and I don’t know if I’ve seen anything actually do that. Then there’s the matter of helping accessibility tech to realise a page change has occurred, and I’m not sure of the state of the art on that, but last time I looked (some years ago) I think it was bogged down in unreliable heuristic land rather than actually being solved.
1) JS history handling is fragile. A single error can break navigation completely. There's no built-in loading indicator so sites are left with no feedback or have bloated progress bars. And nothing automatically solves for deep links if the app doesn't use routes for different views or relies on other events instead of hyperlinks.
2) Servers are very fast and assembling HTML is trivial. Browsers are optimized for downloading, parsing and rendering HTML as it streams in. Using JS to write HTML after making multiple network calls is objectively slower than a single network request that assembles everything on the server close to the datastore with minimal latency.
3) Every other language is faster and more capable on the server than JS, and all major web frameworks have modern component-based UI templating. Interactions with roundtrips are just fine, and some light JS can handle most other scenarios.
> "an actual application"
That's the only reason to use a SPA, not what you mentioned.
All of your benefits seem to come from using only rest APIs to drive to site. That alone can be done with any site, but SPA usually implies more.
> SPAs are great for a number of reasons:
> [...]
> 2. You need a beefier backend.
I don’t work on front-end and am trying to learn from this thread, so I may misunderstand, but that doesn’t look like an advantage to me. Doesn’t “beefier backend” imply “higher costs”?