Safe cell patch

Open a workbook, patch a few cells, and let mutateWorkbookFile decide whether the output is safe to write. This is the smallest possible safe edit and the pattern every other recipe builds on.

import { mutateWorkbookFile, readWorkbookCell } from "@ironsheet/node";

const inputPath = "template.xlsx";
const outputPath = "patched.xlsx";

// mutateWorkbookFile is the recommended safe-write flow: it validates the
// mutated workbook and returns a package diff before committing bytes.
const report = await mutateWorkbookFile(inputPath, outputPath, async (workbook) => {
  await workbook.patchCell("Sheet1", "A1", "Updated by Ironsheet");
  await workbook.patchCell("Sheet1", "B2", 42000);
});

if (!report.wrote) {
  throw new Error(`Output suppressed: ${report.validation.summary.errors} validation error(s)`);
}

console.log("wrote", outputPath);
console.log("validation summary", report.validation.summary);
console.log("package diff summary", report.diff.summary);
console.log("A1 is now", await readWorkbookCell(outputPath, "Sheet1", "A1"));

What the report tells you

• report.wrote — false means Ironsheet refused to write output.xlsx because the mutated workbook failed validation. The two patchCell calls above still ran in memory, but nothing hit disk.
• report.validation.summary — error and warning counts from the same validator workbook.validate() runs. Check this first when wrote is false.
• report.diff.summary — the package-level diff. For a two-cell patch like this, expect changed to reflect the worksheet part that now contains your edits, and everything else in the ZIP to come back unchanged.
• readWorkbookCell reads the value straight back out of the file you just wrote — a quick way to confirm the patch landed where you expect.

Related

• Safe writes — the full WorkbookSafeWriteReport reference.
• Inspect and validate — read a workbook back out without mutating it.