> Except for a user on a lower specced device that can’t performantly handle filtering and joining on that mass of data in JS code, or perhaps can’t even hold the data in memory.

Just how low-spec and/or how much state-data are we talking about here? I ask only because I am downloading an entire dataset and doing all the logic on the client, and my PC is ancient.

I'm on a computer from 2011 (i7 870 @ 2.9GHz with 16MB of RAM), and the client-side filtering I do, even on a few dozens of thousand of records retrieved from the server, still takes under a second.

On my private app, my prospect list containing maybe 4k records, each pretty substantial (as they include history of engagements/interactions with that client) is faster to sort and filter on the client than it is to download the entire list.

I am usually waiting for 10s while the hefty dataset downloads, but the sorting and filtering happens in under a second. I do not consider that a poor UX.

10s is painful. A server-rendered app should be able to deliver that data, already rendered, in closer to a fifth of a second. Fast enough that the user doesn’t even notice any wait.

> 10s is painful. A server-rendered app should be able to deliver that data, already rendered, in closer to a fifth of a second.

How do you know how large the dataset is? All you know from my post is that a dataset that takes 10s to download (I'm indicating the size of it here!) takes under a second to filter and sort.

My point is that if your client-code is taking long to filter and sort, then your dataset is already so large that the user has been waiting a long time for it already; they already know that this dataset takes time.

FWIW, the data is coming in as CSV, compressed, so it's as small as possible. It's not limited by the server. Having it rendered by the server will increase the payload substantially.

The JS processing and rendering time on an underpowered CPU is the issue, not the payload size. It’s difficult to describe how excruciatingly slow some seemingly simple e-commerce and content sites are to render on my 2019 laptop or how slowly they react to something as simple as a mouseover or how they peg the CPU - while absolutely massively complex and large server-rendered HTML loads and renders in an eyeblink.

Which sites are you thinking off?

I can't really speak for those sites anyway, or why they are so slow doing things on the client, but like I said, I've written client-side processing and used my 2011 desktop, and there has been no pegging of the CPU or large latencies when filtering/sorting data client-side.

> while absolutely massively complex and large server-rendered HTML loads and renders in an eyeblink.

I've not had that experience - a full page refresh with about 10MB of data does not happen in an eyeblink. It takes about 6 seconds. There's a minimum amount of time for that data to download, regardless of whether it is pre-rendered into `<table>` elements or whether it is sent as JSON. Turning that JSON into a `<table>` on the client takes about 40ms on my 2011 desktop. Sorting it again takes about 5ms.

For this use-case (fairly large amounts of data), doing a full-page refresh each time the user sets a new sort criteria is unarguably a poorer experience than a bit of JS that goes through the table element and re-orders the `<tr>` elements.

In this case, using server-rendered HTML is always going to be 6000ms whenever the user re-sorts the table. Using a client JS function takes 5ms. On a machine purchased in 2011.

For sorting the table, perhaps. But for displaying the table in the first place? Static HTML is invariably faster in my experience. IMO there is just no excuse for placeholder elements with loading animations on a content or e-commerce site where it should be possible to provide all the content up front and add some very light JS on top to handle things like image carousels.

> But for displaying the table in the first place? Static HTML is invariably faster in my experience.

Okay, lets assume it is faster by whatever the latency is for a network request.

What sort of use-case are we talking about where a table is displayed on a content or e-commerce side and the user is not allowed to re-sort it?

It's all about the user's experience, not the developer's, and I can't see how a UX that prevents sorting is a better UX. Ditto for a sortable table that refreshes the page each time the user sorts it.

What mass of data? Can you give me an example of the kind of device and the kind of use case you're talking about?