From 48fa30af925289c86fc45e2943f2d2027390f7a4 Mon Sep 17 00:00:00 2001
From: Dmitry Istomin <tirojal@gmail.com>
Date: Mon, 11 Sep 2023 11:13:24 +0300
Subject: [PATCH] fix(nuxt): handle optional params within a path segment
 (#23070)

---
 packages/nuxt/src/pages/utils.ts |  2 +-
 packages/nuxt/test/pages.test.ts | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/packages/nuxt/src/pages/utils.ts b/packages/nuxt/src/pages/utils.ts
index 7e20e617b3..e095bd3622 100644
--- a/packages/nuxt/src/pages/utils.ts
+++ b/packages/nuxt/src/pages/utils.ts
@@ -220,7 +220,7 @@ function parseSegment (segment: string) {
         if (c === '[' && state === SegmentParserState.dynamic) {
           state = SegmentParserState.optional
         }
-        if (c === ']' && (state !== SegmentParserState.optional || buffer[buffer.length - 1] === ']')) {
+        if (c === ']' && (state !== SegmentParserState.optional || segment[i - 1] === ']')) {
           if (!buffer) {
             throw new Error('Empty param')
           } else {
diff --git a/packages/nuxt/test/pages.test.ts b/packages/nuxt/test/pages.test.ts
index 8d21d91264..1de27d84f9 100644
--- a/packages/nuxt/test/pages.test.ts
+++ b/packages/nuxt/test/pages.test.ts
@@ -157,6 +157,10 @@ describe('pages:generateRoutesFromFiles', () => {
         { path: `${pagesDir}/[slug].vue` },
         { path: `${pagesDir}/[[foo]]` },
         { path: `${pagesDir}/[[foo]]/index.vue` },
+        { path: `${pagesDir}/optional/[[opt]].vue` },
+        { path: `${pagesDir}/optional/prefix-[[opt]].vue` },
+        { path: `${pagesDir}/optional/[[opt]]-postfix.vue` },
+        { path: `${pagesDir}/optional/prefix-[[opt]]-postfix.vue` },
         { path: `${pagesDir}/[bar]/index.vue` },
         { path: `${pagesDir}/nonopt/[slug].vue` },
         { path: `${pagesDir}/opt/[[slug]].vue` },
@@ -188,6 +192,31 @@ describe('pages:generateRoutesFromFiles', () => {
           file: 'pages/[[foo]]',
           path: '/:foo?'
         },
+        {
+          children: [],
+          path: '/optional/:opt?',
+          name: 'optional-opt',
+          file: `${pagesDir}/optional/[[opt]].vue`
+        },
+        {
+          children: [],
+          path: '/optional/prefix-:opt?',
+          name: 'optional-prefix-opt',
+          file: `${pagesDir}/optional/prefix-[[opt]].vue`
+        },
+
+        {
+          children: [],
+          path: '/optional/:opt?-postfix',
+          name: 'optional-opt-postfix',
+          file: `${pagesDir}/optional/[[opt]]-postfix.vue`
+        },
+        {
+          children: [],
+          path: '/optional/prefix-:opt?-postfix',
+          name: 'optional-prefix-opt-postfix',
+          file: `${pagesDir}/optional/prefix-[[opt]]-postfix.vue`
+        },
         {
           children: [],
           name: 'bar',