fix: headings having duplicate keys

[efekrskl]

Description

Fixes a minor issue where article headings could have duplicate keys, when they share the same title (e.g https://nodejs.org/en/learn/test-runner/mocking, https://nodejs.org/en/learn/diagnostics/memory)

Validation

Related Issues

Check List

• I have read the Contributing Guidelines and made commit messages that follow the guideline.
• I have run pnpm format to ensure the code follows the style guide.
• I have run pnpm test to check if all tests are passing.
• I have run pnpm build to check if the website builds without errors.
• I've covered new added functionality with unit tests if necessary.

[vercel]

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Project	Deployment	Preview	Updated (UTC)
nodejs-org	Ready	Preview	Nov 11, 2025 6:41pm

[Copilot]

Pull Request Overview

This PR fixes a React duplicate key warning issue that occurred when article headings share the same text content. The fix changes the list key from the heading text (head.value) to the unique heading ID (head.data?.id) generated by the rehype-slug plugin.

• Changed the React key for heading list items from text-based to ID-based to ensure uniqueness
• Improved consistency in optional chaining syntax for the href attribute

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.76%. Comparing base (ca6a3dd) to head (69c283b).
⚠️ Report is 9 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #8348   +/-   ##
=======================================
  Coverage   76.76%   76.76%           
=======================================
  Files         118      118           
  Lines        9822     9822           
  Branches      335      335           
=======================================
  Hits         7540     7540           
  Misses       2280     2280           
  Partials        2        2           

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[bjohansebas]

@efekrskl you can do a rebase or make an empty commit so Vercel triggers a new preview, please?. I’m not sure why it failed on Vercel, but it seems that everything is fine in the GitHub action. If the error keeps happening, let us know on Slack

[efekrskl]

@efekrskl you can do a rebase or make an empty commit so Vercel triggers a new preview, please?. I’m not sure why it failed on Vercel, but it seems that everything is fine in the GitHub action. If the error keeps happening, let us know on Slack

Yup, seems to be working fine now