feat(blog): allow processing blog posts through a processBlogPosts function

packages/docusaurus-plugin-content-blog/src/__tests__/blogUtils.test.ts

@@ -14,10 +14,11 @@
   linkify,
   getSourceToPermalink,
   paginateBlogPosts,
+  applyProcessBlogPosts,
   type LinkifyParams,
 } from '../blogUtils';
 import type {BlogBrokenMarkdownLink, BlogContentPaths} from '../types';
-import type {BlogPost} from '@docusaurus/plugin-content-blog';
+import type {BlogPost, BlogPostMetadata} from '@docusaurus/plugin-content-blog';
 
 describe('truncate', () => {
   it('truncates texts', () => {
@@ -237,6 +238,7 @@
         frontMatter: {},
         authors: [],
         formattedDate: '',
+        unlisted: false,
       },
       content: '',
     },
@@ -295,3 +297,49 @@
     } as BlogBrokenMarkdownLink);
   });
 });
+
+const defaultValuesForOtherKeys: Omit<BlogPostMetadata, 'date'> = {
+  source: '',
+  title: '',
+  formattedDate: '',
+  permalink: '',
+  description: '',
+  hasTruncateMarker: false,
+  authors: [],
+  frontMatter: {},
+  tags: [],
+  unlisted: false,
+};
+const createBlogPost = (args: Partial<BlogPost>): BlogPost => ({
+  id: '',
+  metadata: {
+    date: new Date(),
+    ...defaultValuesForOtherKeys,
+    ...args.metadata,
+  },
+  content: args.content || '',
+});
+
+describe('processBlogPosts', () => {
+  const blogPost2022 = createBlogPost({
+    metadata: {date: new Date('2022-01-01'), ...defaultValuesForOtherKeys},
+  });
+  const blogPost2023 = createBlogPost({
+    metadata: {date: new Date('2023-01-01'), ...defaultValuesForOtherKeys},
+  });
+  const blogPost2024 = createBlogPost({
+    metadata: {date: new Date('2024-01-01'), ...defaultValuesForOtherKeys},
+  });
+
+  it('filter blogs', async () => {
+    const processedBlogPosts = applyProcessBlogPosts({
+      blogPosts: [blogPost2022, blogPost2023, blogPost2024],
+      processBlogPosts: ({blogPosts}: {blogPosts: BlogPost[]}) =>
+        blogPosts.filter(
+          (blogPost) => blogPost.metadata.date.getFullYear() === 2024,
+        ),
+    });
+
+    expect(processedBlogPosts).toEqual([blogPost2024]);
+  });
+});

packages/docusaurus-plugin-content-blog/src/blogUtils.ts

@@ -446,3 +446,19 @@ export function linkify({
 
   return newContent;
 }
+
+export async function applyProcessBlogPosts({
+  blogPosts,
+  processBlogPosts,
+}: {
+  blogPosts: BlogPost[];
+  processBlogPosts: PluginOptions['processBlogPosts'];
+}): Promise<BlogPost[]> {
+  const processedBlogPosts = processBlogPosts({blogPosts});
+
+  if (Array.isArray(processedBlogPosts)) {
+    return processedBlogPosts;
+  }
+
+  return blogPosts;
+}

packages/docusaurus-plugin-content-blog/src/index.ts

@@ -20,11 +20,12 @@ import {
   DEFAULT_PLUGIN_ID,
 } from '@docusaurus/utils';
 import {
-  generateBlogPosts,
   getSourceToPermalink,
   getBlogTags,
   paginateBlogPosts,
   shouldBeListed,
+  applyProcessBlogPosts,
+  generateBlogPosts,
 } from './blogUtils';
 import footnoteIDFixer from './remark/footnoteIDFixer';
 import {translateContent, getTranslationFiles} from './translations';
@@ -113,7 +114,11 @@ export default async function pluginContentBlog(
 
       const baseBlogUrl = normalizeUrl([baseUrl, routeBasePath]);
       const blogTagsListPath = normalizeUrl([baseBlogUrl, tagsBasePath]);
-      const blogPosts = await generateBlogPosts(contentPaths, context, options);
+      let blogPosts = await generateBlogPosts(contentPaths, context, options);
+      blogPosts = await applyProcessBlogPosts({
+        blogPosts,
+        processBlogPosts: options.processBlogPosts,
+      });
       const listedBlogPosts = blogPosts.filter(shouldBeListed);
 
       if (!blogPosts.length) {

packages/docusaurus-plugin-content-blog/src/options.ts

@@ -51,6 +51,7 @@ export const DEFAULT_OPTIONS: PluginOptions = {
   authorsMapPath: 'authors.yml',
   readingTime: ({content, defaultReadingTime}) => defaultReadingTime({content}),
   sortPosts: 'descending',
+  processBlogPosts: () => undefined,
 };
 
 const PluginOptionSchema = Joi.object<PluginOptions>({
@@ -134,6 +135,9 @@ const PluginOptionSchema = Joi.object<PluginOptions>({
   sortPosts: Joi.string()
     .valid('descending', 'ascending')
     .default(DEFAULT_OPTIONS.sortPosts),
+  processBlogPosts: Joi.function()
+    .optional()
+    .default(() => DEFAULT_OPTIONS.processBlogPosts),
 }).default(DEFAULT_OPTIONS);
 
 export function validateOptions({

packages/docusaurus-plugin-content-blog/src/plugin-content-blog.d.ts

@@ -335,6 +335,11 @@ yarn workspace v1.22.19image` is a collocated image path, this entry will be the
       defaultReadingTime: ReadingTimeFunction;
     },
   ) => number | undefined;
+
+  export type ProcessBlogPostsFn = (params: {
+    blogPosts: BlogPost[];
+  }) => void | BlogPost[];
+
   /**
    * Plugin options after normalization.
    */
@@ -426,6 +431,8 @@ yarn workspace v1.22.19image` is a collocated image path, this entry will be the
     readingTime: ReadingTimeFunctionOption;
     /** Governs the direction of blog post sorting. */
     sortPosts: 'ascending' | 'descending';
+    /** TODO process blog posts. */
+    processBlogPosts: ProcessBlogPostsFn;
   };
 
   /**

website/docs/api/plugins/plugin-content-blog.mdx

@@ -75,6 +75,7 @@ Accepted fields:
 | `feedOptions.copyright` | `string` | `undefined` | Copyright message. |
 | `feedOptions.language` | `string` (See [documentation](http://www.w3.org/TR/REC-html40/struct/dirlang.html#langcodes) for possible values) | `undefined` | Language metadata of the feed. |
 | `sortPosts` | <code>'descending' \| 'ascending' </code> | `'descending'` | Governs the direction of blog post sorting. |
+| `processBlogPosts` | <code><a href="#ProcessBlogPostsFn">ProcessBlogPostsFn</a> </code> | `undefined` | An optional function which can be used to transform blog posts (filter, modify, delete, etc...). |
 
 ```mdx-code-block
 </APITable>
@@ -131,6 +132,14 @@ type CreateFeedItemsFn = (params: {
 }) => Promise<BlogFeedItem[]>;
 ```
 
+#### `ProcessBlogPostsFn` {#ProcessBlogPostsFn}
+
+```ts
+type ProcessBlogPostsFn = (params: {
+  blogPosts: BlogPost[];
+}) => Promise<void | BlogPost[]>;
+```
+
 ### Example configuration {#ex-config}
 
 You can configure this plugin through preset options or plugin options.