woff-lib

TypeScript WOFF and WOFF2 encoder and decoder. Relies on brotli-lib

Install

npm install woff-lib

Usage

// WOFF2 decode
import { woff2Decode } from 'woff-lib/woff2/decode'
const ttf = await woff2Decode(woff2Data)

// WOFF2 encode
import { woff2Encode } from 'woff-lib/woff2/encode'
const woff2 = woff2Encode(ttfData, { quality: 11 })

// WOFF decode
import { woffDecode } from 'woff-lib/woff/decode'
const ttf = await woffDecode(woffData)

// WOFF encode
import { woffEncode } from 'woff-lib/woff/encode'
const woff = await woffEncode(ttfData)

// Import everything
import { woffDecode, woffEncode, woff2Decode, woff2Encode } from 'woff-lib'

API

woff2Decode

function woff2Decode(data: ArrayBuffer | Uint8Array): Promise<Uint8Array>

Decodes WOFF2 to TTF/OTF. Async to use native Brotli (Node zlib, browser DecompressionStream) when available (falls back to pure JS in Chrome)

woff2Encode

function woff2Encode(
  data: ArrayBuffer | Uint8Array,
  options?: { quality?: number }  // 0-11, default 11
): Uint8Array

Encodes TTF/OTF to WOFF2. Implements glyf/loca and hmtx transforms per spec

woffDecode

function woffDecode(data: ArrayBuffer | Uint8Array): Promise<Uint8Array>

Decodes WOFF to TTF/OTF. Uses native zlib (Node) or DecompressionStream (browser)

woffEncode

function woffEncode(
  data: ArrayBuffer | Uint8Array,
  options?: { level?: number }  // 1-9, default 9
): Promise<Uint8Array>

Encodes TTF/OTF to WOFF. Async to use native zlib (Node) or CompressionStream (browser)

Tree-shaking

Import	Bundle size
woff-lib/woff/decode	~4 KB
woff-lib/woff/encode	~4 KB
woff-lib/woff2/decode	~33 KB
woff-lib/woff2/encode	~24 KB
woff-lib/decode	~37 KB
woff-lib/encode	~24 KB
woff-lib	~60 KB

WOFF2 decoder includes brotli-lib fallback, which is ~80 KB

Performance

Operation	TTF (305 KB)	CFF/OTF (253 KB)	Variable TTF (788 KB)
woff2Encode (q11)	781 ms	860 ms	1,918 ms
woff2Encode (q4)	7.4 ms	5.4 ms	18.3 ms
woff2Decode	2.4 ms	1.6 ms	5.1 ms
woff2Decode (pure JS)	3.3 ms	2.6 ms	7.5 ms
woffEncode	11.3 ms	8.4 ms	23.7 ms
woffDecode	0.8 ms	0.7 ms	2.2 ms

Tested on Apple M2 Max, Node.js 22. woff2Decode uses native Brotli via node:zlib when available, falling back to pure JS (brotli-lib) in browsers without native Brotli decompression (e.g. Chrome). WOFF uses native zlib

Platform support

• Node.js 16+ (uses native zlib)
• Browsers: Chrome 80+, Firefox 113+, Safari 16.4+ (DecompressionStream)

License

MIT

Derived from Google's woff2 (see LICENSE_THIRD_PARTY)

Maintained by @jpt