Svelte 5 Generic component with JSDoc ?

[falco467]

Hi,
we are working i a strictly typed JS + JSDoc environment. It is great that we can write type-safe props with @type and have full type-checking everywhere. We can also use generic functions and types with JSDoc @template {...} T
But it seems that using a generic Svelte component generics="T extends" is only possible with TypeScript?
Is there any trick or any plan to support generic components with JSDoc?

We have a generic table component and it would be great if we could automatic type-safety in our snippets for the columns if we define the component with a generic row type, which would then be inferred by the passed array-type.

[falco467]

If I declare Props dynamic with JSDoc @template T ... I will always get type-errors when using the component, since the component will be instantiated as the concrete type Comp<Prop<T>> and not as a generic Type for which types can be inferred.

The workaround which I found is to explicitly type cast the component to the correct concrete type:

import Select from './Select.svelte'
const SelectNumber = /** @type {import('svelte').Component<import('./Select.svelte').Props<number>,{},"value">} */ (Select)

This works, but is quite cumbersome, since I have to create this cast anytime I want to use the component without errors.

It would be great if Svelte could support type inference by use, like normal generic types and functions do.

Here is a Playground sample with the working work around:
https://svelte.dev/playground/48be5dc1b4c040a8a98f5af6fa1291aa?version=5.2.7

[brunnerh]

Would recommend opening an actual issue in language-tools.