fix(nuxt): fix nested page types in typedPages (#29352)

packages/nuxt/src/pages/module.ts

@@ -170,10 +170,15 @@ export default defineNuxtModule({
           if (nuxt.apps.default) {
             nuxt.apps.default.pages = pages
           }
+          const addedPagePaths = new Set<string>()
           function addPage (parent: EditableTreeNode, page: NuxtPage) {
+            // Avoid duplicate keys in the generated RouteNamedMap type
+            const absolutePagePath = joinURL(parent.path, page.path)
+
             // @ts-expect-error TODO: either fix types upstream or figure out another
             // way to add a route without a file, which must be possible
-            const route = parent.insert(page.path, page.file)
+            const route = addedPagePaths.has(absolutePagePath) ? parent : parent.insert(page.path, page.file)
+            addedPagePaths.add(absolutePagePath)
             if (page.meta) {
               route.addToMeta(page.meta)
             }

test/fixtures/basic-types/pages/param/index.vue

@@ -0,0 +1,12 @@
+<script setup lang="ts">
+definePageMeta({
+  name: 'param2',
+  alias: ['/param-other'],
+})
+</script>
+
+<template>
+  <div>
+    <!--  -->
+  </div>
+</template>

test/fixtures/basic-types/types.ts

@@ -162,6 +162,10 @@ describe('typed router integration', () => {
     // @ts-expect-error this is an invalid param
     router.push({ name: 'param-id', params: { bob: 23 } })
     router.push({ name: 'param-id', params: { id: 4 } })
+    // @ts-expect-error this is an invalid route
+    router.push({ name: 'param' })
+    // @ts-expect-error this is an invalid route
+    router.push({ name: '/param' })
   })
 
   it('correctly reads custom names typed in `definePageMeta`', () => {