(feat) be able to type props/events/slots

[dummdidumm]

Through a new reserved interface ComponentDef

See new tests for examples.

Generics

Problem to be solved: Generics. We cannot use instanceOf(ComponentName) anymore, because this way we cannot pass in the information about the type of the generic.

If we have

Child:

<script lang="ts">
   interface ComponentDef<T> {
        props: {items: T[]},
        events: {itemClick: CustomEvent<T>;}
        slots: {}
   }
</script>
// ...

Parent:

<Child items="{['a', 'stringarray']}" on:itemClick="{iShouldBeOfTypeString => ...}" />

We need a transformation that makes sure that iShouldBeOfTypeString actually is inferred as string. My current idea is to transform this to new Child({props: {...allPropsAndItsValuesThatAreDefinedOnTheChild}}).$on instead of the old instanceOf(Child).$on.

A completely different idea is to somehow use Function Components instead of Class components. But I'm not sure if we can use this with all the other constraints we have.

Thoughts?

[jasonlyu123]

Maybe we can add a dummy helper function like __sveltets_norename or __sveltets_generated to retain the no-rename of old instanceOf

[Evertt]

Hey guys, any idea when this will be completed? 👼
I'm running up against this very issue right now and for now I'm just using any instead of a generic type, but you know, a generic type would be nice. 😁

[dummdidumm]

This implementation will very likely not land in this form. This RFC is where the discussion is happening and the details are specified. After that the implementation will follow.