When viewing a JS code example, the types on hover are missing if the function is JSDoc annotated. This only happens in the JS view.
e.g., https://svelte.dev/docs/kit/routing#server hover over { url } in the function parameters while viewing the JS block. It's different from the TS block which shows the full type. Similarly for RequestHandler. You can view the type in the TS block but not the JS block when hovering over it.