feat(v2): plugins injectHtmlTags + configureWebpack should receive content loaded (#5037)

* more lifecycles should receive plugin loaded content

* refactor docs/blog plugins to use newly injected loaded plugin content instead of a mutable variable

* update lifecycle docs

* update lifecycle docs

* fix failing tests

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

@@ -55,7 +55,7 @@ import {
 export default function pluginContentBlog(
   context: LoadContext,
   options: PluginOptions,
-): Plugin<BlogContent | null> {
+): Plugin<BlogContent> {
   if (options.admonitions) {
     options.remarkPlugins = options.remarkPlugins.concat([
       [admonitions, options.admonitions],
@@ -88,8 +88,6 @@ export default function pluginContentBlog(
   const aliasedSource = (source: string) =>
     `~blog/${posixPath(path.relative(pluginDataDirRoot, source))}`;
 
-  let blogPosts: BlogPost[] = [];
-
   return {
     name: 'docusaurus-plugin-content-blog',
 
@@ -116,10 +114,19 @@ export default function pluginContentBlog(
     async loadContent() {
       const {postsPerPage, routeBasePath} = options;
 
-      blogPosts = await generateBlogPosts(contentPaths, context, options);
+      const blogPosts: BlogPost[] = await generateBlogPosts(
+        contentPaths,
+        context,
+        options,
+      );
 
       if (!blogPosts.length) {
-        return null;
+        return {
+          blogPosts: [],
+          blogListPaginated: [],
+          blogTags: {},
+          blogTagsListPath: null,
+        };
       }
 
       // Colocate next and prev metadata.
@@ -242,7 +249,7 @@ export default function pluginContentBlog(
 
       const {addRoute, createData} = actions;
       const {
-        blogPosts: loadedBlogPosts,
+        blogPosts,
         blogListPaginated,
         blogTags,
         blogTagsListPath,
@@ -275,7 +282,7 @@ export default function pluginContentBlog(
 
       // Create routes for blog entries.
       await Promise.all(
-        loadedBlogPosts.map(async (blogPost) => {
+        blogPosts.map(async (blogPost) => {
           const {id, metadata} = blogPost;
           await createData(
             // Note that this created data path must be in sync with
@@ -403,6 +410,7 @@ export default function pluginContentBlog(
       _config: Configuration,
       isServer: boolean,
       {getJSLoader}: ConfigureWebpackUtils,
+      content,
     ) {
       const {
         rehypePlugins,
@@ -416,7 +424,7 @@ export default function pluginContentBlog(
         siteDir,
         contentPaths,
         truncateMarker,
-        sourceToPermalink: getSourceToPermalink(blogPosts),
+        sourceToPermalink: getSourceToPermalink(content.blogPosts),
         onBrokenMarkdownLink: (brokenMarkdownLink) => {
           if (onBrokenMarkdownLinks === 'ignore') {
             return;
@@ -506,8 +514,8 @@ export default function pluginContentBlog(
       );
     },
 
-    injectHtmlTags() {
-      if (!blogPosts.length) {
+    injectHtmlTags({content}) {
+      if (!content.blogPosts.length) {
         return {};
       }