fix(nuxt): prevent param duplication in typedPages implementation (#31331)

packages/nuxt/src/pages/module.ts

@@ -202,9 +202,17 @@ export default defineNuxtModule({
             // 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 = addedPagePaths.has(absolutePagePath) ? parent : parent.insert(page.path, page.file)
+            const route = addedPagePaths.has(absolutePagePath)
+              ? parent
+              : /^\//.test(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
+                ? rootPage.insert(page.path, page.file)
+                // @ts-expect-error TODO: either fix types upstream or figure out another
+                // way to add a route without a file, which must be possible
+                : parent.insert(page.path, page.file)
+
             addedPagePaths.add(absolutePagePath)
             if (page.meta) {
               route.addToMeta(page.meta)

test/fixtures/basic-types/pages/param/[id].vue

@@ -1,5 +1,5 @@
 <template>
   <div>
-    <!--  -->
+    <NuxtPage />
   </div>
 </template>

test/fixtures/basic-types/pages/param/[id]/view.vue

@@ -0,0 +1,13 @@
+<script setup lang="ts">
+definePageMeta({
+  name: 'param-id-view-custom',
+  // Deliberately passing absolute path here to test if params are not being duplicated in RouteNamedMap
+  path: '/param/:id()/view-custom',
+})
+</script>
+
+<template>
+  <div>
+    <!--  -->
+  </div>
+</template>

test/fixtures/basic-types/types.ts

@@ -206,6 +206,7 @@ describe('typed router integration', () => {
   it('correctly reads custom names typed in `definePageMeta`', () => {
     const router = useRouter()
     router.push({ name: 'some-custom-name' })
+    router.push({ name: 'param-id-view-custom', params: { id: 4 } })
   })
 
   it('allows typing useRoute', () => {
@@ -224,6 +225,9 @@ describe('typed router integration', () => {
     // @ts-expect-error this is an invalid param
     navigateTo({ name: 'param-id', params: { bob: 23 } })
     navigateTo({ name: 'param-id', params: { id: 4 } })
+    // @ts-expect-error this is an invalid param
+    navigateTo({ name: 'param-id-view-custom', params: { bob: 23 } })
+    navigateTo({ name: 'param-id-view-custom', params: { id: 4 } })
   })
 
   it('allows typing middleware', () => {

test/typed-router.test.ts

@@ -0,0 +1,17 @@
+import { readFileSync } from 'node:fs'
+import { resolve } from 'node:path'
+import { fileURLToPath } from 'node:url'
+import { x } from 'tinyexec'
+import { describe, expect, it } from 'vitest'
+
+const rootDir = fileURLToPath(new URL('./fixtures/basic-types', import.meta.url))
+
+describe('typed router integration', () => {
+  it('does not duplicate params in RouteNamedMap when a child route overrides the path with an absolute path', async () => {
+    await x('nuxi', ['prepare', rootDir])
+    const typedRouterDtsFile = resolve(rootDir, '.nuxt/types/typed-router.d.ts')
+    const typedRouterDts = readFileSync(typedRouterDtsFile, 'utf8')
+    expect(typedRouterDts).toContain(`'param-id-view-custom': RouteRecordInfo<'param-id-view-custom', '/param/:id()/view-custom', { id: ParamValue<true> }, { id: ParamValue<false> }>,`)
+    expect(typedRouterDts).not.toContain(`'param-id-view-custom': RouteRecordInfo<'param-id-view-custom', '/param/:id()/view-custom', { id: ParamValue<true>, id: ParamValue<true> }, { id: ParamValue<false>, id: ParamValue<false> }>,`)
+  })
+})