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no-deprecated-html-comments-in-mdx

Disallow deprecated HTML comments in .mdx files and prefer JSX comments for Docusaurus 3.10 strict MDX migration.

Targeted pattern scopeโ€‹

This rule focuses on .mdx content files.

It reports HTML comments such as:

  • <!-- truncate -->
  • <!-- note -->
  • multiline HTML comments inside MDX documents

What this rule reportsโ€‹

This rule reports HTML comments in .mdx files because Docusaurus 3.10 strict MDX guidance prefers JSX comments instead.

Why this rule existsโ€‹

MDX v3 does not support HTML comments, while JSX comment expressions are part of native MDX syntax.

Migrating comments from <!-- ... --> to {/* ... */} makes MDX files more portable across Docusaurus, editors, formatters, and the wider MDX ecosystem.

โŒ Incorrectโ€‹

# My Blog Post

<!-- truncate -->

Content.

โœ… Correctโ€‹

# My Blog Post

{/* truncate */}

Content.

Behavior and migration notesโ€‹

This rule autofixes HTML comments to JSX comments in .mdx files.

It intentionally ignores fenced code blocks so migration examples can stay in documentation.

ESLint flat config exampleโ€‹

import docusaurus2 from "eslint-plugin-docusaurus-2";

export default [docusaurus2.configs["strict-mdx-upgrade"]];

When not to use itโ€‹

Do not use this rule if you are intentionally postponing strict MDX migration or still have tooling that depends on the older HTML comment form.

Rule catalog ID: R114

Further readingโ€‹