From 77a349954c8af114df20bcbe3f2f9d0c0fef83bc Mon Sep 17 00:00:00 2001
From: Jacob Hummer <jcbhmr@outlook.com>
Date: Tue, 24 Oct 2023 20:10:03 +0000
Subject: [PATCH] support site config .extends being an array

---
 __tests__/e2e/.vitepress/config.ts | 14 +++++++++++---
 src/node/config.ts                 |  9 +++++++--
 src/node/siteConfig.ts             |  2 +-
 3 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/__tests__/e2e/.vitepress/config.ts b/__tests__/e2e/.vitepress/config.ts
index 84fc64f2..8ecc514a 100644
--- a/__tests__/e2e/.vitepress/config.ts
+++ b/__tests__/e2e/.vitepress/config.ts
@@ -84,10 +84,18 @@ const sidebar: DefaultTheme.Config['sidebar'] = {
 }
 
 export default defineConfig({
-  title: 'Example',
-  description: 'An example app using VitePress.',
+  extends: [
+    {
+      title: 'Example',
+      description: 'An example app using VitePress.'
+    },
+    {
+      themeConfig: {
+        sidebar
+      }
+    }
+  ],
   themeConfig: {
-    sidebar,
     search: {
       provider: 'local',
       options: {
diff --git a/src/node/config.ts b/src/node/config.ts
index b2425c3e..7824f3e2 100644
--- a/src/node/config.ts
+++ b/src/node/config.ts
@@ -180,8 +180,13 @@ async function resolveConfigExtends(
 ): Promise<UserConfig> {
   const resolved = await (typeof config === 'function' ? config() : config)
   if (resolved.extends) {
-    const base = await resolveConfigExtends(resolved.extends)
-    return mergeConfig(base, resolved)
+    const extendsRaw = [resolved.extends].flat()
+    const manyBases = await Promise.all(
+      extendsRaw.map((config) => resolveConfigExtends(config))
+    )
+    // or reduceRight() depending on which side gets priority
+    const singleBase = manyBases.reduce((prev, curr) => mergeConfig(prev, curr))
+    return mergeConfig(singleBase, resolved)
   }
   return resolved
 }
diff --git a/src/node/siteConfig.ts b/src/node/siteConfig.ts
index 10cd3967..c426d1e5 100644
--- a/src/node/siteConfig.ts
+++ b/src/node/siteConfig.ts
@@ -56,7 +56,7 @@ export interface TransformPageContext {
 
 export interface UserConfig<ThemeConfig = any>
   extends LocaleSpecificConfig<ThemeConfig> {
-  extends?: RawConfigExports<ThemeConfig>
+  extends?: RawConfigExports<ThemeConfig> | RawConfigExports<ThemeConfig>[]
 
   base?: string
   srcDir?: string