`{@const}` inside `{#key}` block

[longnguyen2004]

Describe the problem

Since the current {#key} block operates like a 1-element {#each} block, it should make sense to allow using {@const} inside of {#key} as well.

Describe the proposed solution

Allow the usage of {@const} inside {#key}

Alternatives considered

Use a dummy {#if true} block

{#key ...}
    {#if true}
        {@const ...}
    {/if}
{/key}

Importance

nice to have

[nevis2us]

I second the move. Example use case:

{#key active}
{@const item = items[active]}
...
{/key}

[dummdidumm]

This is allowed in Svelte 5

[longnguyen2004]

Doesn't seem like it is allowed in Svelte 5, I'm still getting the same error

[paoloricciuti]

Closed by #15377

[paoloricciuti]

Closed by #15377