HF-131 (7/7): documentation

[marcin-kordas-hoc]

What and why

Stacked on #1766, the last in this stack. Documentation only.

• Adds the missing #SPILL! row to docs/guide/types-of-errors.md (the type existed and was
  producible before this stack, just undocumented) and a new "Error messages and explanations"
  section explaining what message does and doesn't do: it states the specific cause within an
  error's type, but HyperFormula does not turn it into a longer plain-language explanation or call
  out to an LLM to generate one — an application wanting to rephrase for end users should do so at
  the application layer, using type/message as input.
• Adds a "Finding out where an error came from" section covering originFunction, argumentIndex
  and hasMessage, with an example checked against the engine. The custom-functions.md paragraph
  on hasMessage lives in HF-131 (3/7): a consumer can tell 'no message' from 'empty message' #1763, not here.
• Drops one frontmatter tag. The page carried 11 against the cap of 10 in DOCS_CONTENT_GUIDE.md;
  division by zero is the only tag that is a phrase rather than an error code, and #DIV/0!
  already answers that query.

No src/ changes in this PR.

Verified

• npm run docs:build — clean, both new docs pieces present in rendered output
• Full private test suite reproduced against this branch's tip — no regressions beyond the same
  pre-existing branch-pinning mismatch as the rest of this stack (unaffected by a docs-only change,
  included for completeness since it's the tip of the stack)

Stack

7 of 7 — stacked on #1766. Last PR in the HF-131 stack: #1761 → #1762 → #1763 → #1764 → #1765 →
#1766 → this one.

🤖 Generated with Claude Code

---

Note

Low Risk
Docs-only changes with no runtime or API behavior impact.

Overview
Documentation-only update to types-of-errors.md for the HF-131 stack (no src/ changes).

The error reference table now includes #SPILL! (array result has nowhere to spill), and frontmatter tags swap division by zero for #SPILL! so the page stays within the 10-tag cap while keeping error-code tags consistent.

Two new sections explain how apps should use DetailedCellError: message gives the specific cause within an error type but is not expanded or LLM-generated by HyperFormula (rephrasing belongs in the app layer), and originFunction, argumentIndex, and address help trace which function, argument, or mechanism produced the error, with a short JavaScript example.

^{Reviewed by Cursor Bugbot for commit 67cd26e. Bugbot is set up for automated code reviews on this repo. Configure here.}

[qunabu]

Task linked: HF-131 Verbose and actionable formula error messages

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit 9dbfe89. Configure here.}

[cloudflare-workers-and-pages]

Deploying with    Cloudflare Workers

The latest updates on your project. Learn more about integrating Git with Workers.

Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	hyperformula-docs	67cd26e	Commit Preview URL Branch Preview URL	Sep 15 2026, 08:03 AM

[github-actions]

Performance comparison of head (67cd26e) vs base (1879bbb)

                                     testName |    base |    head | change
--------------------------------------------------------------------------
                                      Sheet A |  499.57 |   496.3 | -0.65%
                                      Sheet B |  155.38 |  154.79 | -0.38%
                                      Sheet T |   143.4 |  140.44 | -2.06%
                                Column ranges |  479.38 |  468.62 | -2.24%
                                Sorted lookup | 14383.4 | 14571.3 | +1.31%
Sheet A:  change value, add/remove row/column |   15.34 |   14.71 | -4.11%
 Sheet B: change value, add/remove row/column |   137.5 |  125.27 | -8.89%
                   Column ranges - add column |  149.23 |  144.43 | -3.22%
                Column ranges - without batch |  460.86 |  450.87 | -2.17%
                        Column ranges - batch |  117.06 |  114.27 | -2.38%

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.45%. Comparing base (1879bbb) to head (67cd26e).

Additional details and impacted files

@@                       Coverage Diff                       @@
##           fix/hf-131-issue-444-addresses    #1767   +/-   ##
===============================================================
  Coverage                           97.45%   97.45%           
===============================================================
  Files                                 195      195           
  Lines                               15868    15868           
  Branches                             3500     3500           
===============================================================
  Hits                                15464    15464           
  Misses                                396      396           
  Partials                                8        8           

🚀 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.

[Tobiadefami]

Could we add { licenseKey: 'gpl-v3' } to the example’s buildFromArray() call? Without it, all three formulas return #LIC! instead of the documented results.