Empty slots forward as non-empty slots

[jtlapp]

I'm racing to meet a deadline and don't have time to create a minimal repro, but when you forward a slot to a child component and the slot happens to be empty, the child component $$slots flags it as non-empty.

I tried:

<slot slot="slotname" name="slotname" />

and

<svelte:fragment slot="slotname">{#if $$slots.slotname}<slot name="slotname" />{/if}{/svelte:fragment}

And the following doesn't work at all:

<slot slot="..." />

My svelte is getting pretty messy without this feature.

[rmunn]

This behavior is explicitly documented in the Svelte docs for $$slots:

Note that explicitly passing in an empty named slot will add that slot's name to $$slots. For example, if a parent passes <div slot="title" /> to a child component, $$slots.title will be truthy within the child.

[jtlapp]

Okay thank you! It seems like this behavior makes slot forwarding incompatible with optional slots.