Cannot prepopulate snippet arguments

[timephy]

Describe the problem

I have a snippet creating a general element with multiple arguments:

{#snippet item(label: string, icon: IconType, selected: boolean)}
    <button
        onclick={onSelected}
    >
        <Icon data={icon} />
        <p>{label}</p>
        {#if selected}
            <p>(selected)</p>
        {/if}
    </button>
{/snippet}

I wanted to pass different variations of this snippet to a child component, but with prepopulated values for label and icon:

<Child
    elements=[
        (selected: boolean) => item("Home", homeIcon, selected),
        (selected: boolean) => item("Settings", settingsIcon, selected),
    ]
/>

While typing this works great with TypeScript, and svelte-check does not report any errors, a runtime error is thrown:

TypeError: Cannot create property 'out' on string 'Home'
    at item
    at Object.item
    at Module.Parent [as default]
    at _page
    at children
    at Module.slot
    at _layout
    at Root
    at Module.render
    at Function._render [as render]

---

I Tried this

Neither specifying the prepopulated function/snippet (like above), nor defining a function homeItem(selected: boolean) { ... } in the <script> works.

I guess this is expected, since it seems that snippets are not "simply functions", and are interpreted differently.

I believe that createRawSnippet can not solve this, since it has to return valid HTML (?), and can not return/render a another snippet?

The only solution currenly

The only solution is to create (in this example) two more {#snippet}s for home and settings and pass these to the Child instead of composing the Snippet in-line.

---

Proposed Solution

I understand that one can not define a snippet inside <script>, as we require the HTML-like syntax of the template, but it would be great if snippets were them "composable" (prepopulate-able) inside JS/TS.

Importance

would make my life easier

[brunnerh]

This is the one feature I would like to see added the most - duplicate of:

• Svelte 5: Avoiding {#snippet} boilerplate with the ability to pass parameters #10678