fix(db-ivm): treat 0 and empty string as valid min/max extremes

[aakbarpour]

🎯 Changes

min() and max() in @tanstack/db-ivm treated a missing accumulator as any falsy value. A group whose true extreme is 0, 0n, or "" therefore returned the wrong aggregate.

The reducers now compare against undefined only.

Fixes #1775

✅ Checklist

• I have tested this code locally with pnpm test.

🚀 Release Impact

• This change affects published code, and I have generated a changeset.
• This change is docs/CI/dev-only (no release).

Summary by CodeRabbit

• Bug Fixes

  • Fixed min and max grouping results so valid falsy values—including 0, 0n, and empty strings—are correctly considered.
  • Grouped calculations now return accurate minimum and maximum values when data includes zero or other falsy values.

• Tests

  • Added coverage for falsy extremes and grouped results containing zero values.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Advanced

Run ID: 45772ad8-fa48-46ab-bbb2-befde4284dcf

📥 Commits

Reviewing files that changed from the base of the PR and between 743d11a and a08f545.

📒 Files selected for processing (3)

• .changeset/minmax-falsy-extremes.md
• packages/db-ivm/src/operators/groupBy.ts
• packages/db-ivm/tests/operators/groupBy.test.ts

Included review availability: Your plan provides up to 8 included reviews per hour; 7 remain after this review.

---

📝 Walkthrough

Walkthrough

The min and max reducers now use undefined as the unset sentinel. New tests cover 0, 0n, empty strings, and grouped results containing zero. A patch changeset documents the correction.

Changes

Falsy min/max aggregate handling

Layer / File(s)	Summary
Update min/max reducer sentinel checks packages/db-ivm/src/operators/groupBy.ts	The min and max reducers now compare against undefined and accept falsy values as valid candidates.
Add regression tests and release metadata packages/db-ivm/tests/operators/groupBy.test.ts, .changeset/minmax-falsy-extremes.md	Tests cover falsy extremes and grouped results containing zero. The changeset declares a patch release.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix · Severity of issue fixed: Medium

Suggested reviewers: kyleamathews

Merge Risk: ⚪ Minimal · up to a08f5

Falsy numeric, bigint, and string extremes are preserved with regression coverage for direct and grouped aggregates. The change is ready to merge.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 2 files. (1 skipped: 1 …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely identifies the main change: treating 0 and empty strings as valid min/max extremes in db-ivm.
Description check	✅ Passed	The description includes the required Changes, Checklist, and Release Impact sections. It explains the bug and fix, reports local testing, identifies the published-code impact, and includes a changese…
Linked Issues check	✅ Passed	The change satisfies #1775. packages/db-ivm/src/operators/groupBy.ts now uses minValue === undefined and maxValue === undefined as the accumulator checks. The reducers compare values with < an…
Out of Scope Changes check	✅ Passed	The changes stay within #1775. The source update fixes the two affected reducers. The added tests verify the regression and grouped behavior. The changeset documents the patch release for `@tanstack/d…

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 2 files. (1 skipped: 1 unsupported.)

• Fix all pre-merge checks with AI

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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.}