feat(*): add Rust based @eslint-markdown/parser for performance

[lumirlumir]

A blazing-fast Markdown parser for ESLint.

Brief Benchmark

• Running npx eslint against a single 200,000-line Markdown file: 47s → 4s
• Parsing only: 25ms -> 2ms

Roadmap

• Thorough review
• Add documentation for @eslint-markdown/parser.
• Battle-test against existing codebases.
• Remove 0.0.0-canary.0 in package.json

References

@eslint/markdown

• Change Request: Support languageOptions.parser to improve parser performance by integrating a Rust parser eslint/markdown#703
• feat: support languageOptions.parser and test with a Rust-based parser eslint/markdown#706

satteri

• Incorrect position offsets and columns for surrogate pairs bruits/satteri#185
• Standalone CR line endings are not reflected in mdast positions bruits/satteri#186
• GFM autolink nodes can be emitted without position information bruits/satteri#187
• markdownToMdast and mdxToMdast should return Root bruits/satteri#191
• Support selecting YAML and TOML front matter independently bruits/satteri#194
• https://github.com/bruits/satteri/security/advisories/GHSA-hx2j-xq45-6xpw
• Native binding version enforcement expects 0.8.1 for satteri 0.9.5 bruits/satteri#209
• Disabling GFM still applies tilde-related emphasis delimiter behavior bruits/satteri#210
• Parenthesized link titles containing an opening parenthesis are not parsed as links bruits/satteri#211
• https://github.com/bruits/satteri/security/advisories/GHSA-7hg6-666q-rcf7

[vercel]

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Project	Deployment	Actions	Updated (UTC)
npm-eslint-markdown-website	Ready	Preview	Aug 21, 2026 4:14pm

[codecov]

Bundle Report

Changes will increase total bundle size by 18.35kB (0.68%) ⬆️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
website-esm	2.7MB	18.35kB (0.68%) ⬆️

Affected Assets, Files, and Routes:

view changes for bundle: website-esm

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
app.js	51 bytes	218.81kB	0.02%
@localSearchIndexroot.*.js	4.1kB	196.72kB	2.13%
docs_packages_parser.*.js (New)	12.48kB	12.48kB	100.0% 🚀
docs_get-started_index.*.js	1.72kB	8.34kB	26.05% ⚠️

Files in docs_packages_parser.*.js:

• ./docs/packages/parser.md → Total Size: 12.44kB

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (bcab65f) to head (fb09ae9).

@@            Coverage Diff            @@
##              main      #638   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           39        40    +1     
  Lines          626       633    +7     
  Branches       137       140    +3     
=========================================
+ Hits           626       633    +7     

Files with missing lines	Coverage Δ
packages/parser/src/index.ts	100.00% <100.00%> (ø)

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[github-actions]

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