[feat] add convenience type for ComponentEvents

[ivanhofer]

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Tests

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This extends the convenience types of #6770 with

• ComponentEvents to get all events of a component
  use-case: wrapping a component and re-declaring its events
  https://github.com/ivanhofer/sveltekit-typescript-showcase/blob/main/src/03-events/04-%24%24Events/Component.svelte
• ComponentEvent to get the type of a single event of a component
  use-case: typing an event handler
  https://github.com/ivanhofer/sveltekit-typescript-showcase/blob/main/src/03-events/02-typed-event-details/Usage.svelte
• ComponentSlots to get all slots of a component
  use-case: none, that I currently can think of, but it makes sense to also provide this type helper

[dummdidumm]

Thank you, this looks good! See review comments for things I'd like to change.

[ignatiusmb]

Hey, thanks for the PR! ComponentEvents is pretty nice to have indeed, though I can't seem to say the same about ComponentEvent. We can already achieve the same thing with ComponentEvents<Component>['close'], and this makes more sense to me as it also aligns with how TypeScript provides their utility types, e.g. Parameters and without the singular Parameter.

[ivanhofer]

Hey, thanks for the PR! ComponentEvents is pretty nice to have indeed, though I can't seem to say the same about ComponentEvent. We can already achieve the same thing with ComponentEvents<Component>['close'], and this makes more sense to me as it also aligns with how TypeScript provides their utility types, e.g. Parameters and without the singular Parameter.

I know I can get a single event with the ComponentEvents<Component>['close'] syntax. But other people may find the syntax confusing. That's why I have added a second type.
Another option could be to create a single ComponentEvents type with an optional second generic. That type then either returns the full object or the type of a single event.

[dummdidumm]

@ignatiusmb has a point here - let's keep it simple for now and remove the ComponentEvent type.

[dummdidumm]

Thank you!

[Conduitry]

This has been released in 3.50.0. Thank you!