Non-blocking state update

[jonybekov]

Hi, there! I was wondering if Svelte has a way to update state in a non-blocking fashion.
Here's artifically slow tabs example. https://svelte.dev/repl/565c333f0ab141c1a97e96f855d2e7d0?version=4.2.12

As you can see, when you switch Tab 2, it prevents tab button from being active until tab content rendering finishes.
It makes the UI feel less snappy.

I was seeking something like useTransition in React: https://react.dev/reference/react/useTransition#marking-a-state-update-as-a-non-blocking-transition

Thanks in advance!

[fry69]

It seems this is a fundamental issue with Svelte and synchronous operations line new Array(). I played around a bit using async functions, but it did not help. The dummyCreate() using setTimeout() does not block btw.

Also I noticed while the REPL does support loading JavaScript files, it does not support loading web workers.

Maybe relevant discussion: #10738

Disclaimer: I am learning and know little about how Svelte works internally.