Not necessarily - although that's usually fine. I prefer a non responsive UI when waiting for io/db, to a poorly implemented background execution where you aren't sure anything is actually happening.
> I prefer a non responsive UI when waiting for io/db, to a poorly implemented background execution where you aren't sure anything is actually happening.
You can't be sure anything is happening on a locked desktop app either though, so at least you can close it gracefully if it's doing that on another thread
IME customers close stuff if Windows shows "Not Responding" but not if you just have a fake progress bar.
But (most) browser apps are single threaded and you can block the UI if you do anything intensive on the client-side.
There quite a few ways around that with async APIs and WebWorkers, even ServiceWorkers now. A lot of devs just don't use them properly.
Edit: Did you mean the browser itself could freeze? That's a thing of the past with Firefox being the last browser to separate the content and chrome process. So the web page may freeze, the browser window itself shouldn't.
Those are relatively new features, and aren't used a whole lot.
WebWorkers are not a new "feature". The last browser to support it was (on desktop) IE in v10 (4 years ago) and on mobile Android 4.4 (3 years ago). Though that doesn't really matter since you can polyfill it, which obviously does not give you multithreading in those older browsers but it still forces you to think async.
Regarding other APIs, a great number has been available since many years, and any newly introduced API since at least 5 years is either non-blocking or async.
In my experiences being forced to use various SPAs from various venders, more often than not async just means I need to behave single threaded rather than the app lest I wish to trigger race conditions that desync the local model and I end up having to hard refresh.
Heh, the MS Windows file/folder permissions tab comes to mind when you mention that. Been single-threaded for 20+ years now. Clicking on the Add... button always freezes the UI while it communicates with the domain controller or whatever it does.
You mean where everything runs on the UI thread? Gotta pass on that. :)