Fix compact star formatter rounding gap at 999.5k+

[kanywst]

Summary

Gemini Code Assist flagged a rounding gap in the manual formatter introduced in #9: 999,999 stars satisfies the >= 1_000 branch but not >= 1_000_000, so (999_999 / 1_000).toFixed(1) resolved to "1000.0" and the function returned "1000.0k" — exactly the failure mode the formatter was meant to prevent.

Replace the magnitude-branching implementation with Intl.NumberFormat({ notation: 'compact', maximumFractionDigits: 1 }), which delegates unit transitions to ICU and rounds 999,999 up to "1M". ICU emits an uppercase K, so we patch it back to lowercase to keep the existing design (small-k thousands, capital-M millions).

Existing assertions are updated to drop the trailing .0 since Intl emits "1k" rather than "1.0k" for exact thousands. A new test pins the edge case at 999,999 directly.

Test plan

• npm run lint
• npm run build
• npm run test -- --run (3 files, 9 tests)

[coderabbitai]

Warning

Rate limit exceeded

@kanywst has exceeded the limit for the number of commits that can be reviewed per hour. Please wait 38 minutes and 27 seconds before requesting another review.

To continue reviewing without waiting, purchase usage credits in the billing tab.

⌛ How to resolve this issue?

After the wait time has elapsed, a review can be triggered using the @coderabbitai review command as a PR comment. Alternatively, push new commits to this PR.

We recommend that you space out your commits to avoid hitting the rate limit.

🚦 How do rate limits work?

CodeRabbit enforces hourly rate limits for each developer per organization.

Our paid plans have higher rate limits than the trial, open-source and free plans. In all cases, we re-allow further reviews after a brief timeout.

Please see our FAQ for further information.

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 15f8260b-4575-49c9-92ca-bc4c7ced92d3

📥 Commits

Reviewing files that changed from the base of the PR and between 87cb847 and 1f12203.

📒 Files selected for processing (2)

• src/lib/format.test.ts
• src/lib/format.ts

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/compact-star-rounding

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[gemini-code-assist]

Code Review

This pull request refactors the formatCompactStars function to use Intl.NumberFormat for compact notation, which simplifies the logic and improves rounding accuracy. The unit tests have been updated to reflect changes in the output format, such as the removal of trailing zeros for whole numbers. A review comment suggests using a global regular expression when replacing the 'K' suffix to ensure robustness across different JavaScript environments.

I am having trouble creating individual review comments. Click here to see my feedback.

src/lib/format.ts (8)

The current implementation uses .replace('K', 'k'), which only replaces the first occurrence of an uppercase 'K'. While this is sufficient for the 'en' locale's compact notation, using a regular expression with the global flag (e.g., replace(/K/g, 'k')) or targeting the suffix specifically (e.g., replace(/K$/, 'k')) is more robust against potential variations in how different JavaScript engines or ICU versions might format the string.

  return COMPACT_FORMATTER.format(count).replace(/K/g, 'k');