Feature/averageifs function

[Tobiadefami]

Context

HyperFormula supports AVERAGEIF and other conditional aggregation functions, but it does not support AVERAGEIFS.

This change adds AVERAGEIFS, allowing values to be averaged when all corresponding criteria are satisfied. It uses the existing conditional aggregation and caching infrastructure and includes function metadata, translations, documentation, and tests.

How did you test your changes?

Added tests covering:

• Required and repeated arguments.
• Invalid criteria and mismatched range dimensions.
• Single and multiple criteria.
• Scalar, reference, range, and calculated-range arguments.
• Error propagation.
• Ignoring non-numeric values in the average range.
• Division-by-zero errors when no numeric values qualify.
• Valid averages equal to zero.
• Conditional aggregation caching.
• Recalculation after changes to the average or criteria ranges.
• Public function metadata.
• The Portuguese translation.

All 28 focused tests passed.

Additionally, I ran:

• npm run bundle:cjs
• npm run docs:generate-function-docs

Both commands completed successfully.

Types of changes

• Breaking change (a fix or a feature because of which an existing functionality doesn't work as
  expected anymore)
• New feature or improvement (a non-breaking change that adds functionality)
• Bug fix (a non-breaking change that fixes an issue)
• Additional language file, or a change to an existing language file (translations)
• Change to the documentation

Related issues:

Checklist:

• I have reviewed the guidelines about [Contributing to HyperFormula](https://
  hyperformula.handsontable.com/guide/contributing.html) and I confirm that my code follows the code style of
  this project.
• I have signed the Contributor License Agreement.
• My change is compliant with the [OpenDocument](https://docs.oasis-open.org/office/OpenDocument/v1.3/
  os/part4-formula/OpenDocument-v1.3-os-part4-formula.html) standard.
• My change is compatible with Microsoft Excel.
• My change is compatible with Google Sheets.
• I described my changes in the [CHANGELOG.md](https://github.com/handsontable/hyperformula/blob/master/
  CHANGELOG.md) file.
• My changes require a documentation update.
• My changes require a migration guide.

---

Note

Low Risk
Additive spreadsheet function using established SUMIFS/AVERAGEIF patterns; no changes to auth, persistence, or core engine behavior.

Overview
Adds AVERAGEIFS, averaging numeric cells in a range when all paired criterion ranges and criteria match—aligned with Excel/Google Sheets and the existing SUMIFS / AVERAGEIF pattern.

Implementation wires averageifs in ConditionalAggregationPlugin through computeConditionalAggregationFunction with AverageResult composition, repeatLastArgs: 2 for extra range/criterion pairs, and #DIV/0! when no qualifying numeric values exist.

Also updates the changelog, statistical function metadata, and localized function names across language packs.

^{Reviewed by Cursor Bugbot for commit 8f54b3a. Bugbot is set up for automated code reviews on this repo. Configure here.}

[cla-external-contractor-signup]

@Tobiadefami thanks for the pull request. No CLA step needed here — our records show you signed the Contributor License Agreement on 2026-07-31. That signature came from our previous signing form and has been carried over, so there is nothing for you to re-sign.

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Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	hyperformula-docs	8f54b3a	Commit Preview URL Branch Preview URL	Aug 13 2026, 09:12 AM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.31%. Comparing base (61ead73) to head (8f54b3a).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1732   +/-   ##
========================================
  Coverage    97.31%   97.31%           
========================================
  Files          195      195           
  Lines        15719    15742   +23     
  Branches      3455     3393   -62     
========================================
+ Hits         15297    15320   +23     
- Misses         414      422    +8     
+ Partials         8        0    -8     

Files with missing lines	Coverage Δ
src/i18n/languages/csCZ.ts	100.00% <ø> (ø)
src/i18n/languages/daDK.ts	100.00% <ø> (ø)
src/i18n/languages/deDE.ts	100.00% <ø> (ø)
src/i18n/languages/enGB.ts	100.00% <ø> (ø)
src/i18n/languages/esES.ts	100.00% <ø> (ø)
src/i18n/languages/fiFI.ts	100.00% <ø> (ø)
src/i18n/languages/frFR.ts	100.00% <ø> (ø)
src/i18n/languages/huHU.ts	100.00% <ø> (ø)
src/i18n/languages/idID.ts	100.00% <ø> (ø)
src/i18n/languages/itIT.ts	100.00% <ø> (ø)
... and 9 more

... and 5 files with indirect coverage changes

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[github-actions]

Performance comparison of head (8f54b3a) vs base (61ead73)

                                     testName |    base |    head | change
--------------------------------------------------------------------------
                                      Sheet A |  504.43 |  489.18 | -3.02%
                                      Sheet B |  165.44 |  160.25 | -3.14%
                                      Sheet T |  144.35 |  140.02 | -3.00%
                                Column ranges |  531.09 |  520.14 | -2.06%
                                Sorted lookup | 15846.1 | 15836.9 | -0.06%
Sheet A:  change value, add/remove row/column |   16.93 |   16.91 | -0.12%
 Sheet B: change value, add/remove row/column |  153.33 |  141.33 | -7.83%
                   Column ranges - add column |  164.26 |  159.02 | -3.19%
                Column ranges - without batch |  483.76 |  500.67 | +3.50%
                        Column ranges - batch |  124.29 |  127.76 | +2.79%

[marcin-kordas-hoc]

Nothing to change here — this is exactly right, and it is actually stricter than its own sibling. averageif's mapFunction a few lines up (around line 206) has no CellError check at all, so an error cell in the averaged range gets silently treated as blank there, while this new averageifs correctly propagates it. Same story as the zero-average fix in #1733 — nice consistency instinct there.

Not asking for a change in this PR — averageif's behavior predates this change and isn't something #1732 broke. But since #1733 is already touching this exact file for the zero-average fix, it might be a cheap one to fold in there too, if you're up for it. Totally optional either way.

Why it matters: a user migrating a single-criterion AVERAGEIF formula to AVERAGEIFS would suddenly start seeing errors that were silently hidden before — confusing, but not something this PR introduced or is responsible for fixing.

[marcin-kordas-hoc]

Hey @Tobiadefami — one process thing unrelated to the code itself (which looks solid, see the review above): the paired hyperformula-tests PR seems to have slipped through for this one. The branch feature/averageifs-function is there with real, good tests (function-averageifs.spec.ts + the metadata/i18n/custom-functions updates — I read through them, nice coverage on error propagation, caching, and CRUD recalculation), but there's no PR wrapping it, unlike TAKE (#28) and CHOOSECOLS (#34) which both have theirs open.

Could you open a PR there for this branch? Same thing seems to have happened for #1733's companion branch (fix/averageif-zero-average) — also has commits, also no PR yet. Both should be quick since the work itself is already done and pushed, just need the PR opened so they're visible for review the same way your other two are.

Nothing else blocking here — just flagging it now so it's not a surprise closer to merge.