refactor: use plugin-kit native method

[yeonjuan]

Checklist

• Addresses an existing open issue: fixes [REFACTOR] Replace getLocFromIndex and getIndexFromLoc methods with ESLint's native APIs #413

Description

[Copilot]

Pull Request Overview

This PR refactors the HTMLSourceCode implementation to leverage native methods from the updated @eslint/plugin-kit library (version 0.4.1), eliminating duplicate code.

• Upgrades @eslint/plugin-kit from 0.3.1 to 0.4.1
• Removes custom implementations of getIndexFromLoc and getLocFromIndex methods (now provided by TextSourceCodeBase)
• Changes export pattern from class to factory function for better encapsulation

Reviewed Changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
yarn.lock	Updates @eslint/plugin-kit to 0.4.1 and adds @eslint/core 0.17.0 dependency
packages/eslint-plugin/package.json	Updates @eslint/plugin-kit dependency version to 0.4.1
packages/eslint-plugin/lib/languages/html-source-code.js	Removes duplicate getIndexFromLoc/getLocFromIndex methods and exports factory function instead of class
packages/eslint-plugin/lib/languages/html-language.js	Updates to use createHTMLSourceCode factory function instead of HTMLSourceCode class
packages/eslint-plugin/tests/languages/html-source-code.test.js	Updates test imports and adds type assertion helper function

Comments suppressed due to low confidence (1)

packages/eslint-plugin/tests/languages/html-source-code.test.js:47

• This guard always evaluates to false.

  if (value === undefined && value === null) {

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

The logical operator should be || (OR) instead of && (AND). A value cannot be both undefined and null simultaneously, so this condition will never be true and the function will never throw an error.

if (value === undefined || value === null) {

Suggested change

	if (value === undefined && value === null) {
	if (value === undefined || value === null) {

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.76%. Comparing base (e88504c) to head (e43159e).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #447      +/-   ##
==========================================
+ Coverage   98.56%   98.76%   +0.20%     
==========================================
  Files          84       84              
  Lines        2791     2761      -30     
  Branches      778      759      -19     
==========================================
- Hits         2751     2727      -24     
+ Misses         40       34       -6     

Flag	Coverage Δ
unittest	98.76% <100.00%> (+0.20%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...kages/eslint-plugin/lib/languages/html-language.js	97.14% <100.00%> (ø)
...es/eslint-plugin/lib/languages/html-source-code.js	100.00% <100.00%> (+6.12%)	⬆️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.