Whether it runs in a server-side component (SvelteKit)
Function returned from
onMount and callback passed to
onDestroy are both called before a Svelte component is unmounted(destroyed).
If a function is returned from
onMount, it will be called when the component is unmounted. — onMount, Svelte Docs
Therefore, they can be used to clear intervals or remove event listeners.
Schedules a callback to run immediately before the component is unmounted. — onDestroy, Svelte Docs
onDestroy runs inside a server-side component. This affects SSR(server-side-rendering). Therefore in SvelteKit, it is advised to clear intervals and remove event listeners using
onDestroy, this is the only one that runs inside a server-side component. — onDestroy, Svelte Docs