docs: add `transformHtml` and `buildEnd` hooks (#1317)

Co-authored-by: Divyansh Singh <40380293+brc-dd@users.noreply.github.com>

docs/config/app-configs.md

@@ -246,3 +246,59 @@ export default {
   cleanUrls: 'with-subfolders'
 }
 ```
+
+## Build Hooks
+
+VitePress build hooks allow you to add new functionality and behaviors to your website:
+
+- Sitemap
+- Search Indexing
+- PWA
+
+### transformHtml
+
+- Type: `( code: string, id: string, ctx: TransformContext ) => Awaitable<string | void>`
+
+`transformHtml` is a build hook to transform the content of each page before saving to disk (SSG).
+
+::: warning
+Modifying the html content may cause hydration problems in runtime.
+:::
+
+```ts
+import { defineConfig } from 'vitepress'
+
+export default defineConfig({
+  /* other vitepress options */
+  async transformHtml(code, id, context) {
+  }
+})
+```
+
+```ts
+interface TransformContext {
+  siteConfig: SiteConfig
+  siteData: SiteData
+  pageData: PageData
+  title: string
+  description: string
+  head: HeadConfig[]
+  content: string
+}
+```
+
+### buildEnd
+
+- Type: `(siteConfig: SiteConfig) => Awaitable<void>`
+
+`buildEnd` is a build CLI hook, it will run after build (SSG) finish but before VitePress CLI process exits.
+
+```ts
+import { defineConfig } from 'vitepress'
+
+export default defineConfig({
+  /* other vitepress options */
+  async buildEnd(siteConfig) {
+  }
+})
+```

src/node/config.ts

@@ -99,18 +99,20 @@ export interface UserConfig<ThemeConfig = any> {
   transformHtml?: (
     code: string,
     id: string,
-    ctx: {
-      siteConfig: SiteConfig
-      siteData: SiteData
-      pageData: PageData
-      title: string
-      description: string
-      head: HeadConfig[]
-      content: string
-    }
+    ctx: TransformContext
   ) => Awaitable<string | void>
 }
 
+export interface TransformContext {
+  siteConfig: SiteConfig
+  siteData: SiteData
+  pageData: PageData
+  title: string
+  description: string
+  head: HeadConfig[]
+  content: string
+}
+
 export type RawConfigExports<ThemeConfig = any> =
   | Awaitable<UserConfig<ThemeConfig>>
   | (() => Awaitable<UserConfig<ThemeConfig>>)