[isamu]

Summary

Splits calculator.ts, which scoria flags as god-file (over 500 lines). Behaviour does not change.

• src/engine/rangeReading.ts: the range reads offered to a formula — getRangeValues, getRangeValuesRaw, getRangeValuesKeepingBlanks, countFilledCells, getRangeGrid — and the helpers they use.
  • They lived as closures inside openSheet. Now rangeReaders({ resolveSheetData, sourceSheetOf, evaluateValue }) builds them from what they need.
  • evaluateValue is defined later inside openSheet, so it is passed as a function that calls it.
• src/engine/sheetPreparation.ts: preprocessDates, which turns dates written as text into serial numbers, and sheetsDateSource, where a date's display format is read from.
• src/engine/openSheetTypes.ts: the types calculator.ts and rangeReading.ts share (CellPosition, OpenSheet, ResolvedSheetRef and others).
• normalizeData stays in calculator.ts. It is public, and tests import it from there. Its doc comment had become separated from it and now sits on it again.

Items to Confirm

• The one change beyond moving code: countFilledCells had repeated sourceSheetOf's body (which sheet's cells as written to read) inline; it now calls sourceSheetOf. The two are the same expression.
• Behaviour is unchanged. Old (origin/main) and new were run side by side and compared:
  • every formula in the tests (corpusdiff.mts);
  • formulas over generated sheets;
  • cross-sheet reads over generated sheets (COUNTA, SUM, AVERAGE, SUMIF, COUNT over a whole column, ROWS, INDEX, TRANSPOSE, SUM of SORT, and reads of a sheet that does not exist), whose source cells mix blanks, ="", text, errors, numbers and a SEQUENCE that spills.
  • Every result was identical: values and errors.
• The public exports are unchanged. The runtime export lists of src/engine/index.ts, src/index.ts and src/core/index.ts are the same on origin/main and here.
• yarn lint, yarn typecheck, yarn build, yarn test, yarn test:engine, run-all-fixtures.ts, test:calculator and test:scripts pass. oxlint reports nothing.

User Prompt

• https://github.com/receptron/GUIChatPluginSpreadsheet/security/code-scanning — fix whatever can be fixed, all together.
• Do more.

🤖 Generated with Claude Code

work in GUIChatPluginSpreadsheet

[isamu]

CODEX VERDICT: LGTM
Read SHA: 7571ecd

Axis	Result
correctness and edge cases	none
security (injection / path traversal / code evaluation)	none
tests: does a test go red if the new behaviour breaks	none; yarn typecheck passed and yarn test:engine passed all 2,216 tests. Vitest could not start because the existing vite.config.ts uses __dirname under --configLoader runner.
API / schema / wire / on-disk compatibility	none
consistency with the rest of the codebase	none
i18n lockstep (src/lang has 8 locales)	none; no locale changes are needed
TIER C behaviour preservation	none
move fidelity	none; the extracted functions match origin/main:src/engine/calculator.ts, and the factory only closes over resolveSheetData, sourceSheetOf, and the evaluateValue thunk
countFilledCells equivalence	none; sourceSheetOf(range) is equivalent to the former inline splitSheetReference/sourceName lookup
ordering / TDZ	none; rangeReaders construction only creates closures, so the evaluateValue thunk is not invoked before evaluateValue is initialized
public surface	none; export lists of src/engine/index.ts, src/index.ts, and src/core/index.ts are unchanged, and normalizeData remains importable from calculator.ts
differential coverage	none; the corpus, generated, and cross-sheet cases described reach the moved range readers, spill preparation, blank-aware/count reads, grid reads, date preparation, and cross-sheet state paths

FINDINGS COMPLETE: I read every hunk of the diff and this is every finding I have.