Do you use .svelte.ts for all files, or only for the ones that need it?

[jjgmckenzie]

I believe this is a pretty meaningless / stylistic difference, but is there any compiler magic?

[brunnerh]

You only need it when using runes like $state & $effect.

I would only add .svelte. if necessary, it is wasteful to let the Svelte compiler process files that do not need processing.