feat(nuxt): add types for default NuxtLink slot (#31104)

packages/nuxt/src/app/components/nuxt-link.ts

@@ -2,17 +2,21 @@ import type {
   AllowedComponentProps,
   AnchorHTMLAttributes,
   ComputedRef,
-  DefineComponent,
-  InjectionKey, PropType,
+  DefineSetupFnComponent,
+  InjectionKey,
+  PropType,
+  SlotsType,
+  UnwrapRef,
+  VNode,
   VNodeProps,
 } from 'vue'
 import { computed, defineComponent, h, inject, onBeforeUnmount, onMounted, provide, ref, resolveComponent } from 'vue'
-import type { RouteLocation, RouteLocationRaw, Router, RouterLink, RouterLinkProps, useLink } from 'vue-router'
+import type { RouteLocation, RouteLocationRaw, Router, RouterLink, RouterLinkProps, UseLinkReturn, useLink } from 'vue-router'
 import { hasProtocol, joinURL, parseQuery, withTrailingSlash, withoutTrailingSlash } from 'ufo'
 import { preloadRouteComponents } from '../composables/preload'
 import { onNuxtReady } from '../composables/ready'
 import { navigateTo, resolveRouteObject, useRouter } from '../composables/router'
-import { useNuxtApp, useRuntimeConfig } from '../nuxt'
+import { type NuxtApp, useNuxtApp, useRuntimeConfig } from '../nuxt'
 import { cancelIdleCallback, requestIdleCallback } from '../compat/idle-callback'
 
 // @ts-expect-error virtual file
@@ -28,7 +32,8 @@ const NuxtLinkDevKeySymbol: InjectionKey<boolean> = Symbol('nuxt-link-dev-key')
  * `<NuxtLink>` is a drop-in replacement for both Vue Router's `<RouterLink>` component and HTML's `<a>` tag.
  * @see https://nuxt.com/docs/api/components/nuxt-link
  */
-export interface NuxtLinkProps extends Omit<RouterLinkProps, 'to'> {
+export interface NuxtLinkProps<CustomProp extends boolean = false> extends Omit<RouterLinkProps, 'to'> {
+  custom?: CustomProp
   /**
    * Route Location the link should navigate to when clicked on.
    */
@@ -102,6 +107,24 @@ export interface NuxtLinkOptions extends
   prefetchOn?: Exclude<NuxtLinkProps['prefetchOn'], string>
 }
 
+type NuxtLinkDefaultSlotProps<CustomProp extends boolean = false> = CustomProp extends true
+  ? {
+      href: string
+      navigate: () => Promise<void>
+      prefetch: (nuxtApp?: NuxtApp) => Promise<void>
+      route: (RouteLocation & { href: string }) | undefined
+      rel: string | null
+      target: '_blank' | '_parent' | '_self' | '_top' | (string & {}) | null
+      isExternal: boolean
+      isActive: false
+      isExactActive: false
+    }
+  : UnwrapRef<UseLinkReturn>
+
+type NuxtLinkSlots<CustomProp extends boolean = false> = {
+  default?: (props: NuxtLinkDefaultSlotProps<CustomProp>) => VNode[]
+}
+
 /* @__NO_SIDE_EFFECTS__ */
 export function defineNuxtLink (options: NuxtLinkOptions) {
   const componentName = options.componentName || 'NuxtLink'
@@ -466,14 +489,19 @@ export function defineNuxtLink (options: NuxtLinkOptions) {
             isExternal: isExternal.value || hasTarget.value,
             isActive: false,
             isExactActive: false,
-          })
+          } satisfies NuxtLinkDefaultSlotProps<true>)
         }
 
         // converts `""` to `null` to prevent the attribute from being added as empty (`href=""`)
         return h('a', { ref: el, href: href.value || null, rel, target }, slots.default?.())
       }
     },
-  }) as unknown as DefineComponent<NuxtLinkProps>
+    // }) as unknown as DefineComponent<NuxtLinkProps, object, object, ComputedOptions, MethodOptions, object, object, EmitsOptions, string, object, NuxtLinkProps, object, SlotsType<NuxtLinkSlots>>
+  }) as unknown as new<CustomProp extends boolean = false>(props: NuxtLinkProps<CustomProp>) => InstanceType<DefineSetupFnComponent<
+    NuxtLinkProps<CustomProp>,
+    [],
+    SlotsType<NuxtLinkSlots<CustomProp>>
+  >>
 }
 
 export default defineNuxtLink(nuxtLinkDefaults)

packages/nuxt/test/nuxt-link.test.ts

@@ -55,8 +55,9 @@ const nuxtLink = (
 ): { type: string, props: Record<string, unknown>, slots: unknown } => {
   const component = defineNuxtLink({ componentName: 'NuxtLink', ...nuxtLinkOptions })
 
-  const [type, _props, slots] = (component.setup as unknown as (props: NuxtLinkProps, context: { slots: Record<string, () => unknown> }) =>
-  () => [string, Record<string, unknown>, unknown])(props, { slots: { default: () => null } })()
+  const [type, _props, slots] = (
+    component as unknown as { setup: (props: NuxtLinkProps, context: { slots: Record<string, () => unknown> }) => () => [string, Record<string, unknown>, unknown] }
+  ).setup(props, { slots: { default: () => null } })()
 
   return { type, props: _props, slots }
 }