Extending Blog Plugin to Save Tags to Global Data – Getting "path" Argument Error

[bogminic]

Hi Docusaurus team,

I'm trying to extend the blog plugin to save all blog tags to globalData. I followed the approach suggested in #5856, but it's not working. I'm getting the following error:

[ERROR] Site reload failure
TypeError: The "path" argument must be of type string. Received undefined

My Setup

I created a custom blog plugin (blogPluginEnhanced.ts) and registered it in docusaurus.config.ts. The plugin extends the default blog plugin and adds blogTags to globalData.

📌 CodeSandbox Reproduction: https://codesandbox.io/p/devbox/musing-dhawan-h9r7lr

🔹 Docusaurus version: 3.7.0
🔹 Node version: 20

Here’s my enhanced blog plugin:

import type { LoadContext, Plugin } from '@docusaurus/types';
import blogPlugin from '@docusaurus/plugin-content-blog';
import type { PluginOptions as BlogPluginOptions } from '@docusaurus/plugin-content-blog';

export default async function blogPluginEnhanced(
  context: LoadContext,
  options: BlogPluginOptions
): Promise<Plugin> {

  console.log('blogPluginEnhanced options received:', options);

  const blogPluginInstance = await blogPlugin(context, { 
    ...options,
  }) as unknown as Plugin;

  console.log('blogPluginInstance:', blogPluginInstance);

  return {
    ...blogPluginInstance,
    name: 'blog-plugin-enhanced',

    async contentLoaded({ content, actions }) {
      if (blogPluginInstance.contentLoaded) {
        await blogPluginInstance.contentLoaded({ content, actions });
      }

      const { setGlobalData } = actions;
      const { blogTags } = content as { blogTags?: string[] };

      setGlobalData({ blogTags });

      console.log('Enhanced blog content loaded:', content);
    },
  };
}

In docusaurus.config.ts, I register it like this:

plugins: [
  [
    blogPluginEnhanced,
    {
      path: "blog",
      routeBasePath: "blog",
      postsPerPage: "ALL",
      blogSidebarCount: 0,
      showReadingTime: true,
    },
  ],
],

Issue

The site fails to reload with:

TypeError: The "path" argument must be of type string. Received undefined

I suspect that something in the plugin options is causing path to be undefined. Any ideas on how to fix this?

Thanks in advance! 🚀

[slorber]

hey @bogminic

The problem in your exemple is that you don't re-export the validateOptions, leading to your enhanced blog plugin options not be "normalized" and having undefined options while our default plugin provides default values.

I've fixed your code and provided a runnable example for everyone to look at here:

#4138 (comment)

[bogminic]

Thanks a lot, @slorber ! Your guidance helped me fix the issue. Adding validateOptions and disabling the default blog plugin (blog: false in presets inside docusaurus.config.ts) solved everything. Really appreciate your help! 🚀