Install

@office-kit/xlsx ships as ESM-only. Pick the entry that matches your runtime.

Package install

pnpm add @office-kit/xlsx
# or
npm install @office-kit/xlsx
# or
bun add @office-kit/xlsx

Requires Node >=18.18 for the built-in Web Streams, Blob, and fetch globals. Modern browsers (Chromium, Firefox, Safari with Web Streams) work with the streaming entry. Bun and Deno work via Web Streams.

Subpath entries

Import	Use case
`@office-kit/xlsx`	Full library: workbook model, charts, drawings.
`@office-kit/xlsx/streaming`	Read-only iter + write-only append. Browser-safe.
`@office-kit/xlsx/node`	Filesystem `fromFile` / `toFile` + Node `Readable` / `Writable` glue, plus the full lib.

Bundle budgets, min + brotli:

@office-kit/xlsx ≤ 120 KB (currently ~78 KB)
@office-kit/xlsx/streaming ≤ 80 KB (currently ~47 KB)

All exports are side-effect-free ("sideEffects": false), so unused chart / drawing / pivot code drops out under any modern bundler.

TypeScript

Types are bundled. tsconfig.json should have "moduleResolution": "bundler" (or "node16" / "nodenext") so the subpath entries resolve.

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "ESNext",
    "moduleResolution": "bundler",
    "strict": true
  }
}

What’s not in the box

ZIP64 write — fflate’s writer doesn’t emit ZIP64 EOCD, so we fail fast on workbooks with > 65 535 entries. Read works.
Random-access streaming reader — the SAX iterRows API is in place; per-cell random access against a streaming source is buffered.
Encrypted xlsx decryption — we detect CFB Compound Documents and throw a clear error pointing at msoffcrypto-tool; decrypt first, then load.

Next: Getting started →