feat: siteConfig.markdown.parseFrontMatter hook (#9624)

packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/simple-site/docusaurus.config.js

@@ -11,4 +11,16 @@ module.exports = {
   url: 'https://your-docusaurus-site.example.com',
   baseUrl: '/',
   favicon: 'img/favicon.ico',
+  markdown: {
+    parseFrontMatter: async (params) => {
+      // Reuse the default parser
+      const result = await params.defaultParseFrontMatter(params);
+      if (result.frontMatter.last_update?.author) {
+        result.frontMatter.last_update.author =
+          result.frontMatter.last_update.author +
+          ' (processed by parseFrontMatter)';
+      }
+      return result;
+    },
+  },
 };

packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/index.test.ts.snap

@@ -463,7 +463,7 @@ exports[`simple website content: data 1`] = `
   "frontMatter": {
     "title": "Custom Last Update",
     "last_update": {
-      "author": "Custom Author",
+      "author": "Custom Author (processed by parseFrontMatter)",
       "date": "1/1/2000"
     }
   }
@@ -686,7 +686,7 @@ exports[`simple website content: data 1`] = `
   "frontMatter": {
     "title": "Last Update Author Only",
     "last_update": {
-      "author": "Custom Author"
+      "author": "Custom Author (processed by parseFrontMatter)"
     }
   }
 }",

packages/docusaurus-plugin-content-docs/src/__tests__/docs.test.ts

@@ -567,14 +567,14 @@ describe('simple site', () => {
       description: 'Custom last update',
       frontMatter: {
         last_update: {
-          author: 'Custom Author',
+          author: 'Custom Author (processed by parseFrontMatter)',
           date: '1/1/2000',
         },
         title: 'Custom Last Update',
       },
       lastUpdatedAt: new Date('1/1/2000').getTime() / 1000,
       formattedLastUpdatedAt: 'Jan 1, 2000',
-      lastUpdatedBy: 'Custom Author',
+      lastUpdatedBy: 'Custom Author (processed by parseFrontMatter)',
       sidebarPosition: undefined,
       tags: [],
       unlisted: false,
@@ -607,13 +607,13 @@ describe('simple site', () => {
       description: 'Only custom author, so it will still use the date from Git',
       frontMatter: {
         last_update: {
-          author: 'Custom Author',
+          author: 'Custom Author (processed by parseFrontMatter)',
         },
         title: 'Last Update Author Only',
       },
       lastUpdatedAt: 1539502055,
       formattedLastUpdatedAt: 'Oct 14, 2018',
-      lastUpdatedBy: 'Custom Author',
+      lastUpdatedBy: 'Custom Author (processed by parseFrontMatter)',
       sidebarPosition: undefined,
       tags: [],
       unlisted: false,
@@ -685,7 +685,7 @@ describe('simple site', () => {
       description: 'Custom last update',
       frontMatter: {
         last_update: {
-          author: 'Custom Author',
+          author: 'Custom Author (processed by parseFrontMatter)',
           date: '1/1/2000',
         },
         title: 'Custom Last Update',

packages/docusaurus-plugin-content-docs/src/docs.ts

@@ -15,7 +15,7 @@ import {
   getFolderContainingFile,
   getContentPathList,
   normalizeUrl,
-  parseMarkdownString,
+  parseMarkdownFile,
   posixPath,
   Globby,
   normalizeFrontMatterTags,
@@ -140,13 +140,23 @@ async function doProcessDocMetadata({
   env: DocEnv;
 }): Promise<DocMetadataBase> {
   const {source, content, contentPath, filePath} = docFile;
-  const {siteDir, i18n} = context;
+  const {
+    siteDir,
+    i18n,
+    siteConfig: {
+      markdown: {parseFrontMatter},
+    },
+  } = context;
 
   const {
     frontMatter: unsafeFrontMatter,
     contentTitle,
     excerpt,
-  } = parseMarkdownString(content);
+  } = await parseMarkdownFile({
+    filePath,
+    fileContent: content,
+    parseFrontMatter,
+  });
   const frontMatter = validateDocFrontMatter(unsafeFrontMatter);
 
   const {