Transitions are not triggered for the else of an each-else block

[GrygrFlzr]

Describe the bug
When using an {#each} {:else} block, the contents of the {:else} block do not trigger transitions.

To Reproduce
https://svelte.dev/repl/132758f597224a71a8cd520793fe100f?version=3.23.0

1. Click the x buttons to remove items
2. Observe the lack of intro transition for the each-else upon removing the last item
3. Reset to observe lack of outro transition for the each-else

Expected behavior
I expect the behavior to match having a separate {#if array.length === 0} block: triggering transitions.

Information about your Svelte project:

• Your browser and the version: Google Chrome 81.0.4044.138 (Official Build) (64-bit) (cohort: Stable)
• Your operating system: Windows 10 Version 1909 (OS Build 18363.836)
• Svelte version: 3.23.0

Severity
Low priority - easy workaround using a separate {#if} block.

[pushkine]

svelte/src/compiler/compile/render_dom/wrappers/EachBlock.ts

Lines 307 to 308 in f111cf6

	${each_block_else}.c();
	${each_block_else}.m(${update_mount_node}, ${update_anchor_node});

svelte/src/compiler/compile/render_dom/wrappers/EachBlock.ts

Lines 323 to 324 in f111cf6

	${each_block_else}.c();
	${each_block_else}.m(${update_mount_node}, ${update_anchor_node});

@transition_in(${each_block_else}, 1);

I can't rn but you'd just need to insert that line at those two places

<script>
   export let arr = ["a"];
   function foo(node){
        return { tick(t){ node.foo = t; }, duration: 100 }
   }
</script>
{#each arr as v}
    {v}
    {:else}
    <div transition:foo>empty</div>
{/each}

export default {
    test({ component, target, assert, raf }){
       assert.htmlEqual(target.innerHtml, "a");
       component.arr = [];
       assert.htmlEqual(target.innerHtml, "<div>empty</div>");
       raf.tick(50);
       assert.equal(target.querySelector("div").foo, 50);
    }
}

test for it

[Conduitry]

Fixed in 3.24.1 - https://svelte.dev/repl/132758f597224a71a8cd520793fe100f?version=3.24.1

[gbouteiller]

Hello @Conduitry ,
I have tried with a simple example but it doesn't seem to work. Maybe I'm doing something wrong : https://svelte.dev/repl/5270fd96846945bba36a1c7a908d8e6b?version=3.29.4