@sheetwrite/xlsx

Optional deterministic OOXML table and workbook backends for @sheetwrite/core. Core does not depend on this package. It uses the pinned fflate codec for bounded ZIP processing.

Install and register

npm install @sheetwrite/core @sheetwrite/xlsx

Register once before calling any core XLSX function or grid.exportXlsx():

import "@sheetwrite/xlsx/register";
import {
  fromXlsxTable,
  fromXlsxWorkbook,
  toXlsxTable,
  toXlsxWorkbook,
} from "@sheetwrite/core";

The registration entry is idempotent. Importing @sheetwrite/xlsx itself is side-effect free. Explicit composition is available through registerXlsxBackends(), sheetwriteWorkbookBackend, sheetwriteTableImportBackend, and sheetwriteTableExportBackend.

Without registration, core XLSX functions identify the missing optional package. CSV and TSV do not require this package.

Table and workbook APIs

• toXlsxTable(workbook, store, options) and fromXlsxTable(bytes, options) exchange the active or first sheet with a first-row header. Table conversion is in-memory and intentionally reduced-fidelity.
• toXlsxWorkbook(snapshotOrGrid, options) and fromXlsxWorkbook(bytes, options) preserve multiple sheets, formula source, supported styles and number formats, validations, notes, merges, dimensions, frozen panes, named ranges, and versioned Sheetwrite metadata.

See XLSX import and XLSX export.

New in 0.6.0

• Kept parts. Workbook import and export keep unmodeled charts, pivot tables, images, VBA and other package parts as compressed bytes in WorkbookSnapshot.workbook.xlsxSource. Cell edits drop kept charts and pivots with a warning; structural edits drop affected images. maxPreservedBytes defaults to 64 MiB; graphs over the limit are dropped with a warning. Table autofilter rules, sort state, calculated-column formulas and totals-row functions also round-trip. See Kept parts and round trips.
• Streaming. toXlsxTableStream and toXlsxWorkbookStream return a ReadableStream<Uint8Array>. fromXlsxWorkbookFile imports a Blob without buffering every part. Import parses each worksheet from bounded chunks, so its peak memory is lower. See Large files and streaming.
• Formulas and calculation. Import reads iterate, iterateCount and iterateDelta from <calcPr>, and export writes them. Formulas with intersection, union and 3-D references stay as Excel text.
• LibreOffice round trip. Import and export fixes cover vertical alignment, column widths, automatic row heights and hyperlink text and styles. Imported cells without vertical alignment now sit at the bottom, as in Excel. LibreOffice 26.8 round-trip results record producer differences separately; they do not establish full Excel or Google Sheets compatibility. See LibreOffice compatibility.

Limits and safety

Every path shares XlsxWorkbookOptions. maxCells defaults to 1,000,000 logical cells. resourceLimits can lower bounds for compressed input, generated output, archive entries, compression ratio, individual and aggregate inflated bytes, sheets, rows, columns, merges, shared strings, styles, XML elements, XML depth, attributes, and text nodes. Invalid overrides fail before codec work; exceeded bounds throw XlsxResourceError. signal is checked before and between bounded operations. Unsupported content is dropped only with a structured onWarning notification.

The reader preflights the complete ZIP central directory and OPC relationship graph before inflating referenced parts. DTDs and custom XML entities are rejected. Applications accepting untrusted files should set host-specific limits lower than the defaults when appropriate.

Framework toolbar XLSX actions call the core backend contract. Applications enabling those actions must register this package explicitly or lazily import @sheetwrite/xlsx/register immediately before use.