Browser usage

Use @ironsheet/browser when workbook bytes come from a Blob, File, ArrayBuffer, or a browser fetch response instead of the filesystem.

npm install @ironsheet/browser

import {
  inspectWorkbookArchiveFromBlob,
  openWorkbookFromBlob,
  writeWorkbookToBlobSafely
} from "@ironsheet/browser";

const archive = await inspectWorkbookArchiveFromBlob(file);
if (!archive.accepted) {
  throw new Error(archive.issues[0]?.message);
}

const workbook = await openWorkbookFromBlob(file);
await workbook.patchCell("Sheet1", "B2", "Hello from the browser");

const result = await writeWorkbookToBlobSafely(workbook);
if (!result.wrote) {
  throw new Error("Ironsheet refused to write an invalid workbook");
}

const output = result.blob;

The same workbook engine and lossless guarantees apply as in Node — only IO and compression differ. Every method documented in Workbook API is available on the workbook object returned by openWorkbookFromBlob.

How it adapts the core engine

The browser adapter uses CompressionStream and DecompressionStream with deflate-raw. @ironsheet/core only requires a CompressionAdapter boundary — it does not import Node's zlib, so the same engine runs unmodified in both environments.

Browser-safe writes

The browser package cannot own a filesystem transaction like @ironsheet/node, but it can still refuse invalid output. writeWorkbookToBlobSafely validates the in-memory package before creating a downloadable Blob:

const workbook = await openWorkbookFromBlob(file);

await workbook.patchNamedRange("RevenueRange", [["North", 42000]]);
const result = await writeWorkbookToBlobSafely(workbook);
if (!result.wrote) throw new Error("workbook failed validation");

const output = result.blob;

inspectWorkbookArchiveFromBlob reads ZIP metadata without inflating worksheet XML. Use it before opening untrusted files to enforce compressed, uncompressed, entry-count, compression-ratio, and worksheet-size limits.

See it in a real browser workflow

The free Excel Table Refresher uses these public APIs inside a Web Worker to replace an Excel table from CSV without uploading either file.