From 3d0d8314631b9bc7e98aa98b6fd45ad674e6eb05 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Damian=20G=C5=82owala?= <damian.glowala.rebkow@gmail.com>
Date: Mon, 10 Feb 2025 18:10:10 +0100
Subject: [PATCH] fix(nuxt): delete existing properties in app config HMR
 (#30918)

---
 packages/nuxt/src/app/config.ts     | 7 +++++++
 packages/nuxt/src/core/templates.ts | 4 ++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/packages/nuxt/src/app/config.ts b/packages/nuxt/src/app/config.ts
index 476f828abf..4a677359cd 100644
--- a/packages/nuxt/src/app/config.ts
+++ b/packages/nuxt/src/app/config.ts
@@ -54,6 +54,13 @@ export function useAppConfig (): AppConfig {
   return nuxtApp._appConfig
 }
 
+export function _replaceAppConfig (newConfig: AppConfig) {
+  const appConfig = useAppConfig()
+
+  deepAssign(appConfig, newConfig)
+  deepDelete(appConfig, newConfig)
+}
+
 /**
  * Deep assign the current appConfig with the new one.
  *
diff --git a/packages/nuxt/src/core/templates.ts b/packages/nuxt/src/core/templates.ts
index a42e141637..15da3975cd 100644
--- a/packages/nuxt/src/core/templates.ts
+++ b/packages/nuxt/src/core/templates.ts
@@ -425,7 +425,7 @@ export const appConfigTemplate: NuxtTemplate = {
   write: true,
   getContents ({ app, nuxt }) {
     return `
-import { updateAppConfig } from '#app/config'
+import { _replaceAppConfig } from '#app/config'
 import { defuFn } from 'defu'
 
 const inlineConfig = ${JSON.stringify(nuxt.options.appConfig, null, 2)}
@@ -433,7 +433,7 @@ const inlineConfig = ${JSON.stringify(nuxt.options.appConfig, null, 2)}
 // Vite - webpack is handled directly in #app/config
 if (import.meta.hot) {
   import.meta.hot.accept((newModule) => {
-    updateAppConfig(newModule.default)
+    _replaceAppConfig(newModule.default)
   })
 }