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