Spreadsheet

A quote as a spreadsheet: column letters, row numbers, a formula bar and cell formulas with A1 references – =B2*C2*(1-D2), =SUM(E2:E6), =IF(E8>=1000,0,49). Change a quantity and everything that depends on it calculates again. One call builds the sheet; MIT-licensed, no dependencies.

const { tableModel, tableOptions } = SpreadsheetFactory.create({
  data: [
    ["Item", "Qty", "Price", "Net"],
    ["Laptop", 4, 1299, "=B2*C2"],
    ["Monitor", 8, 349, "=B3*C3"],
    ["Total", "", "", "=SUM(D2:D3)"]
  ]
});
const tableScope = new TableScope(host, tableModel, new SimpleDomService(), tableOptions, new EventAdapter());
tableScope.firstInit();
new FormulaBar(barHost, tableScope.getApi());   // optional: address box + formula input

Excel-style editing: type to overwrite, F2 to edit, Enter/Tab move, Delete clears, Ctrl+Enter fills the selection.
Formulas: 70 Excel functions, $A$1, ranges, #DIV/0! and #CIRC!; while typing, references are colored and arrow keys or the mouse point at cells (F4 toggles $). Formulas are parsed, never run as JavaScript.
Copy & paste with Excel and Google Sheets (Ctrl+C / Ctrl+X / Ctrl+V), the fill handle, undo and redo (Ctrl+Z / Ctrl+Y).
Insert and delete rows and columns (right-click): references follow, a deleted one becomes #REF!.
Excel export with real formulas, sorting and filtering keep the references, a million empty rows cost nothing.

Docs: instructions.md 6.20 – 6.25 · API: SpreadsheetFactory, FormulaBar, TableApi.insertRows.