PM
<Items let:index>
{#if index === 13}
<InsertedBlock />
{/if}
</Items>
Size: a a a
PM
<Items let:index>
{#if index === 13}
<InsertedBlock />
{/if}
</Items>
ДБ
{#each items as item, index}
<slot {index} />
...
{/each}
PM
A
ДБ
PM
A
ДБ
PM
PM
PM
PM
A
PM
PM
A
PM
A