Optimize parser hot-paths by j9t · Pull Request #347 · j9t/html-minifier-next

j9t · 2026-08-30T14:06:06Z

Summary by CodeRabbit

Performance
- Improved HTML parsing and minification performance, especially for common ASCII tag names and end tags.
- Reduced overhead when processing trailing whitespace and repeated tags.
Bug Fixes
- Improved handling of non-ASCII tag names during minification.
- Updated tag-closing whitespace behavior for more consistent output.
Chores
- Updated the package version to 8.3.1.
- Refreshed several dependency versions.
Documentation
- Added changelog entries describing the parser performance improvements.

Replaced regex-based tag matching with manual character scans to minimize overhead. Adjusted functions like `parseStartTag`, `matchEndTag`, and `matchTagClose` to use fast-path ASCII processing while maintaining compatibility with existing logic. (This commit message was AI-generated.) Signed-off-by: Jens Oliver Meiert <jens@meiert.com>

Signed-off-by: Jens Oliver Meiert <jens@meiert.com>

socket-security · 2026-08-30T14:06:27Z

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Package	Supply Chain Security	Quality
@types/node@26.2.0 ⏵ 26.4.0	⁺¹	⁺¹
vite@8.2.1 ⏵ 8.2.2		⁺¹
terser@5.50.0 ⏵ 5.51.2	⁺¹
svgo@4.0.2 ⏵ 4.1.0	⁺¹

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coderabbitai · 2026-08-30T14:07:01Z

No actionable comments were generated in the recent review. 🎉

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Run ID: c76b96e3-7e5d-4ee5-a6ee-d18e3aa59e1f

📥 Commits

Reviewing files that changed from the base of the PR and between ae919c5 and 7ce3069.

📒 Files selected for processing (4)

backtest/html-minifier-next.config.json
src/htmlminifier.js
src/htmlparser.js
test/html.test.js

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Walkthrough

The parser and minifier replace selected regular-expression checks with character-code scans. The parser reuses lowercased tag names and packs tag-close results. Tests cover non-ASCII tag names. Package metadata and the changelog advance to version 8.3.1.

Changes

Parser and minifier performance changes

Layer / File(s)	Summary
Parser tag scanning and state reuse `src/htmlparser.js`, `test/html.test.js`	The parser scans common ASCII tag names directly, falls back to the qname regex when needed, packs tag-close results into an integer, reuses lowercased tag names for `prevTag`, and tests non-ASCII tag names.
Minifier end-tag scanning `src/htmlminifier.js`, `backtest/html-minifier-next.config.json`	The minifier uses a hand-rolled end-tag matcher and a direct character-code check for trailing `>`. The backtest configuration disables newlines before tag closes.
Release metadata and dependency ranges `package.json`, `CHANGELOG.md`	The package version changes to `8.3.1`, dependency ranges are updated, and the changelog records the parser performance changes.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to 7ce30

This PR optimizes parser and minifier hot paths while preserving the existing parser interface and fallback behavior; no actionable merge-blocking risk remains beyond normal checks and review.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 70.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 10 functions across 3 files. (1 skipped: …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: parser hot-path performance optimizations, including hand-scanned tag matching and reduced redundant work.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 70.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 10 functions across 3 files. (1 skipped: 1 unsupported.)

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Commit unit tests in branch perf/parser-hot-paths

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Copilot

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Moved `matchPlainEndTag` to improve function organization and reduce duplication. Updated related tests to ensure correct handling of edge cases with non-ASCII tag names. (This commit message was AI-generated.) Signed-off-by: Jens Oliver Meiert <jens@meiert.com>

…maxLineLength`) Signed-off-by: Jens Oliver Meiert <jens@meiert.com>

j9t added 3 commits August 30, 2026 16:02

docs: add perf optimization note

109b21c

Signed-off-by: Jens Oliver Meiert <jens@meiert.com>

chore: update version (and deps while at it)

ae919c5

Signed-off-by: Jens Oliver Meiert <jens@meiert.com>

j9t requested a lite review from Copilot August 30, 2026 14:10

Copilot AI reviewed Aug 30, 2026

j9t added 2 commits August 30, 2026 16:31

chore: disable noNewlinesBeforeTagClose (needs not-to-be-provided `…

7ce3069

…maxLineLength`) Signed-off-by: Jens Oliver Meiert <jens@meiert.com>

j9t merged commit 7d43ecd into main Aug 30, 2026
10 checks passed

j9t deleted the perf/parser-hot-paths branch August 30, 2026 14:51

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Optimize parser hot-paths - #347

Optimize parser hot-paths#347
j9t merged 5 commits into
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perf/parser-hot-paths

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j9t commented Aug 30, 2026 •

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