I had an issue in Svelte 5 where I tried to use .focus() but it only worked in SSR, not when SSR was disabled.

const patternSelector = document.querySelector<HTMLButtonElement>("#nejime button")!;
patternSelector.focus();

Dominic from the Svelte team explained that SvelteKit tries to restore focus and this conflicted with the focus() I was trying to execute. To fix this I could use queueMicrotask() which makes sure my code runs after SvelteKit is done.

const patternSelector = document.querySelector<HTMLButtonElement>("#nejime button")!;
queueMicrotask(() => {
  patternSelector.focus();
});

Thanks Dominic! 😊