What & why

Approximate MATCH, VLOOKUP, HLOOKUP and XLOOKUP returned #N/A (or, in descending mode, the wrong position) when the sorted search range contained genuinely empty cells. Excel 2021 and Google Sheets skip empty cells when computing the lower/upper bound; HyperFormula instead landed on an empty cell during binary search (its EmptyValue Symbol never matched the key). [HF-223]

Root cause

findLastOccurrenceInOrderedRange (src/interpreter/binarySearch.ts): compare() ranks EmptyValue below every value, breaking the sort invariant the binary search relies on, and the typeof foundValue !== typeof searchKey guard then turned a landing-on-empty into #N/A. Shared by approximate MATCH(±1), sorted VLOOKUP/HLOOKUP, and XLOOKUP(searchMode ±2).

Fix

• The ordered search now runs over a compacted list of non-empty cell indices and maps the result back to the original index space, so empty cells keep their slots and the matched non-empty cell's original 1-based position is reported unchanged.
• AdvancedFind.findNormalizedValue skips EmptyValue on its in-memory ordered path for the same reason.
• Empty strings are unaffected (text ranks above numbers, so they still terminate a numeric run). Exact match (matchType 0) is untouched.

Performance & edge cases

• Complexity: the empty-skip pre-scan is O(n) over the search range, trading away binary search's O(log n) guarantee. This is required for correctness — with empty cells interspersed the search predicate is no longer monotonic, so the binary search cannot run directly on the original range (rationale documented inline in binarySearch.ts). A future optimization can keep O(log n) when the range is statically known to be empty-free.
• All-empty range: returns NOT_FOUND directly instead of falling through to the lower/upper-bound edge-case logic (which could otherwise return offset 0).
• Approximate-bound stepping: the "next" position steps to the next non-empty index, not foundIndex + 1, so skipped empty slots never shift the reported position.

Excel / Google Sheets parity

Behaviour verified against the latest Excel and Google Sheets, including exact-vs-blank, empty-string-not-skipped, and the descending early-stop case.

Tests

Public test suite: handsontable/hyperformula-tests#17 (matching branch task/hf-223-match-empty-cells).

Definition of Done

• Production code + JSDoc
• Tests (hyperformula-tests#17, matching branch)
• Changelog
• i18n — N/A (shared-logic fix, no function add/rename)
• Docs — N/A (was a bug, not a documented limitation)