feat: transformPageData hook (#1492)

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

docs/config/app-configs.md

@@ -318,6 +318,28 @@ export default {
 }
 ```
 
+### transformPageData
+
+- Type: `(pageData: PageData) => Awaitable<Partial<PageData> | { [key: string]: any } | void>`
+
+`transformPageData` is a hook to transform the `pageData` of each page. You can directly mutate `pageData` or return changed values which will be merged into PageData.
+
+
+```ts
+export default {
+  async transformPageData(pageData) {
+    pageData.contributors = await getPageContributors(pageData.relativePath)
+  }
+
+  // or return data to be merged
+  async transformPageData(pageData) {
+    return {
+      contributors: await getPageContributors(pageData.relativePath)
+    }
+  }
+}
+```
+
 ### buildEnd
 
 - Type: `(siteConfig: SiteConfig) => Awaitable<void>`

src/node/config.ts

@@ -108,6 +108,13 @@ export interface UserConfig<ThemeConfig = any> {
     id: string,
     ctx: TransformContext
   ) => Awaitable<string | void>
+
+  /**
+   * PageData transform hook: runs when rendering markdown to vue
+   */
+  transformPageData?: (
+    pageData: PageData
+  ) => Awaitable<Partial<PageData> | { [key: string]: any } | void>
 }
 
 export interface TransformContext {
@@ -138,6 +145,7 @@ export interface SiteConfig<ThemeConfig = any>
     | 'buildEnd'
     | 'transformHead'
     | 'transformHtml'
+    | 'transformPageData'
   > {
   root: string
   srcDir: string
@@ -224,7 +232,8 @@ export async function resolveConfig(
     cleanUrls: userConfig.cleanUrls || 'disabled',
     buildEnd: userConfig.buildEnd,
     transformHead: userConfig.transformHead,
-    transformHtml: userConfig.transformHtml
+    transformHtml: userConfig.transformHtml,
+    transformPageData: userConfig.transformPageData
   }
 
   return config

src/node/markdownToVue.ts

@@ -3,6 +3,7 @@ import path from 'path'
 import c from 'picocolors'
 import LRUCache from 'lru-cache'
 import { resolveTitleFromToken } from '@mdit-vue/shared'
+import { SiteConfig } from './config'
 import { PageData, HeadConfig, EXTERNAL_URL_RE, CleanUrlsMode } from './shared'
 import { slash } from './utils/slash'
 import { getGitTimestamp } from './utils/getGitTimestamp'
@@ -37,7 +38,8 @@ export async function createMarkdownToVueRenderFn(
   isBuild = false,
   base = '/',
   includeLastUpdatedData = false,
-  cleanUrls: CleanUrlsMode = 'disabled'
+  cleanUrls: CleanUrlsMode = 'disabled',
+  siteConfig: SiteConfig | null = null
 ) {
   const md = await createMarkdownRenderer(srcDir, options, base)
   pages = pages.map((p) => slash(p.replace(/\.md$/, '')))
@@ -131,7 +133,7 @@ export async function createMarkdownToVueRenderFn(
       }
     }
 
-    const pageData: PageData = {
+    let pageData: PageData = {
       title: inferTitle(md, frontmatter, title),
       titleTemplate: frontmatter.titleTemplate as any,
       description: inferDescription(frontmatter),
@@ -144,6 +146,16 @@ export async function createMarkdownToVueRenderFn(
       pageData.lastUpdated = await getGitTimestamp(file)
     }
 
+    if (siteConfig?.transformPageData) {
+      const dataToMerge = await siteConfig.transformPageData(pageData)
+      if (dataToMerge) {
+        pageData = {
+          ...pageData,
+          ...dataToMerge
+        }
+      }
+    }
+
     const vueSrc = [
       ...injectPageDataCode(
         sfcBlocks?.scripts.map((item) => item.content) ?? [],

src/node/plugin.ts

@@ -95,7 +95,8 @@ export async function createVitePressPlugin(
         config.command === 'build',
         config.base,
         lastUpdated,
-        cleanUrls
+        cleanUrls,
+        siteConfig
       )
     },