Install

npm install @jetstreamapp/simple-excel

Entry points

Import	Contents
@jetstreamapp/simple-excel	Everything: createWorkbookWriter, openWorkbook, the sinks, sniff, sourceFrom, XlsxError and the types
@jetstreamapp/simple-excel/node	The same surface re-exported, plus fromFile, toFile, toWritable and nodeDeflater. See Node

Both entries ship ESM and CommonJS builds with TypeScript declarations. The core entry is browser-safe: it has no node: imports and no DOM references beyond TextEncoder, TextDecoder, CompressionStream, DecompressionStream and a duck-typed Blob, so it works unchanged in a Web Worker, an MV3 extension service worker and an Electron renderer.

import { collectToBytes, createWorkbookWriter, isXlsxError, openWorkbook, sniff, sourceFrom } from '@jetstreamapp/simple-excel';
import type { CellInput, CellStyle, OpenOptions, Workbook, WorkbookWriterOptions } from '@jetstreamapp/simple-excel';

Environment requirements

Feature	Used for	Minimum
Web Streams (WritableStream)	Stream sinks and the compression pump	Chrome 103+, Firefox 113+, Safari 16.4+, Node 20+
CompressionStream('deflate-raw')	Compressing zip entries on write	Chrome 103+, Firefox 113+, Safari 16.4+, Node 20+
DecompressionStream('deflate-raw')	Inflating zip entries on read	same
TextEncoder / TextDecoder	UTF-8 on both sides	universal on the above
Blob	collectToBlob() only	optional; collectToBytes() needs no Blob

package.json declares engines.node >= 20.

caution

Node has had CompressionStream since 18, but it only accepts the deflate-raw format from 21.2. On an earlier Node the writer falls back to stored (uncompressed) parts; pass nodeDeflater() from the /node entry to keep files compressed — it uses zlib and works on every supported version. It is a good default for server-side writes anyway, because it lets you pick a compression level.

When CompressionStream is missing

hasNativeDeflate() tells you whether the platform has it at all. If it does not, the writer stores every part uncompressed (zip method 0) instead of failing. The file is a valid .xlsx that every reader opens; it is just several times larger. In Node you can always get real compression by passing the zlib-backed deflater:

import { createWorkbookWriter, hasNativeDeflate } from '@jetstreamapp/simple-excel';
import { nodeDeflater, toFile } from '@jetstreamapp/simple-excel/node';

const workbook = createWorkbookWriter(toFile('out.xlsx'), {
  deflater: hasNativeDeflate() ? undefined : nodeDeflater(),
});

collectToBlob() throws UNSUPPORTED_ENVIRONMENT where there is no Blob; use collectToBytes() or a stream sink there.

Verifying the install

import { collectToBytes, createWorkbookWriter } from '@jetstreamapp/simple-excel';

const sink = collectToBytes();
const workbook = createWorkbookWriter(sink);
const sheet = workbook.addSheet('Sheet1', { header: ['A', 'B'] });
await sheet.writeRow([1, 2]);
await sheet.close();
await workbook.close();
const bytes = sink.result(); // a Uint8Array holding a complete .xlsx

sink.result() on collectToBytes is synchronous and only valid after close() has resolved; on collectToBlob it returns a promise.